Berubah warna ketika sudah pernah mengisi form

Jadi permasalahanya ketika saya sudah mengisi form nilai maka baris tabel/button berubah warna atau button menjadi disabled untuk menandakan bahwa sudah pernah mengisi
 image.png 

<table id="example2" class="table table-bordered table-hover">
                    <thead>
                      <tr bgcolor="#66B2E5">
                        <th>No</th>
                        <th>Mata Kuliah</th>
                        <th>Dosen</th>
                        <th>Semester</th>
                        <th>Periode</th>
                        <th>Nilai</th>
                      </tr>
                    </thead>
                    <tbody>
                      <?php ;
               
                      $sql_topik1 = mysqli_query($db,"SELECT * FROM tb_jenis_pertanyaan") or die ($db->error);
                                while($data_topik1 = mysqli_fetch_array($sql_topik1))  ?>
                      <?php 
                      $batas = 10;
                      $halaman = isset($_GET['halaman'])?(int)$_GET['halaman'] : 1;
                      $halaman_awal = ($halaman>1) ? ($halaman * $batas) - $batas : 0;  
               
                      $previous = $halaman - 1;
                      $next = $halaman + 1;
                      
                      $data = mysqli_query($db,"SELECT * from tb_matkul");
                      $jumlah_data = mysqli_num_rows($data);
                      $total_halaman = ceil($jumlah_data / $batas);
               
                      $sql_topik = mysqli_query($db,"SELECT * FROM tb_matkul WHERE semester=1 ORDER BY nama_dosen ASC limit $halaman_awal, $batas") or die ($db->error);
                      $nomor = $halaman_awal+1;
                                while($data_topik = mysqli_fetch_array($sql_topik)) { ?>
                                    <tr>
                                        <td align="center"><?php echo $nomor++; ?></td>	
                                        <td id=""><?php echo $data_topik['matkul']; ?></td>
                                        <td><?php echo $data_topik['nama_dosen']; ?></td>
                                        <td><?php echo $data_topik['semester']; ?></td>
                                        <td><?php echo $data_topik['periode']; ?></td>                       
                                        <td>
                                        <a class="btn btn-success fa fa-pencil" href="?page=matkul&action=nilai&id=<?php echo $data_topik['id_matkul']; ?>"> Pilih&nbsp;</a>
                                    </tr>
                                <?php
                                } ?>

kemudian setelah di klik button pilih maka akan menampilkan form dan berikut programnya :

<form method="POST">
                <?php 
                include '../koneksi/koneksi.php';
                $id_matkul =@$_GET["id_matkul"];
                $sql_topik_id = mysqli_query($db, "SELECT * FROM tb_matkul WHERE id_matkul='$id'") or die ($db->error);
                $data_topik_id = mysqli_fetch_array($sql_topik_id);
                ?>
                    <div class="form-group">
                      <input type="text" value="Mata Kuliah : <?php echo $data_topik_id['matkul']; ?>" class="form-control col-md-6" readonly>
                    </div>
                   <div class="form-group">
                      <input type="text" value="Dosen &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;: <?php echo $data_topik_id['nama_dosen']; ?>" class="form-control col-md-6" readonly>
                    </div>
                    <div class="form-group">
                      <input type="text" value="Semester &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;: <?php echo $data_topik_id['semester']; ?>" class="form-control col-md-6" readonly>
                    </div>
                    <div class="form-group">
                      
                      <input type="text" value="Periode &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;: <?php echo $data_topik_id['periode']; ?>" class="form-control col-md-6" readonly>
                    </div>
                    </form>
                <div class="form-group">
                <?php
                if (!isset($_SESSION['submit'])) {
                $_SESSION['kirim_jawaban'] = true;
                }
                ?>
                <form method="POST"><br>
                <table id="example2" class="table table-bordered table-hover">
                <thead>
                <tr bgcolor="#ffab72">
                    <th>No</th>
                    <th>Jenis / Kategori</th>
                    <th>Pertanyaan</th>
                    <th>Bobot</th>
                </tr>
            </thead>              
                      <?php
                      $no=1;
                      $sql_topik = mysqli_query($db,"SELECT * FROM tb_pertanyaan ORDER BY jenis_pertanyaan ASC") or die ($db->error);;
                while ($data_topik = mysqli_fetch_array($sql_topik)) {
                ?>
            <tbody>
                <tr>
                    <td><?php echo $no++;?></td>
                    <input type="text" hidden="" name="nama_dosen[]" value="<?php echo $data_topik_id['nama_dosen']; ?>">
                    <input type="text" hidden="" name="matkul[]" value="<?php echo $data_topik_id['matkul']; ?>">
                    <input type="text" hidden="" name="semester[]" value="1">
                    <td><input type="text" hidden="" name="jenis_pertanyaan[]" value="<?php echo $data_topik['jenis_pertanyaan'];?>"><?php echo $data_topik['jenis_pertanyaan'];?></td>
                    <td><input type="text" hidden="" name="pertanyaan[]" value="<?php echo $data_topik['pertanyaan'];?>"><?php echo $data_topik['pertanyaan'];?></td>
                    <td>
                    <select name="bobot[]" class="form-control" required="">
                        <option value="">- Pilih -</option>
                    <?php
                    $sql_bobot = mysqli_query($db, "SELECT * from tb_bobot") or die ($db->error);
                    while($data_bobot = mysqli_fetch_array($sql_bobot)) {
                    echo '<option value="'.$data_bobot['bobot'].'">'.$data_bobot['bobot'].'</option>';
                    ?>
                    <?php
                    }
                    ?>
                    </select></td>
                    <input type="text" hidden="" name="nama_mhs[]" value="<?php echo $_SESSION['nama_user1'];?>">
                </tr>
            </tbody>
            <?php
                } 
            }
            ?>
        </table>
        <button type="submit" name="kirim_jawaban" value="Kirim Jawaban" class="btn btn-primary fa fa-save">&nbsp;Kirim</button>
        <button type="reset" value="Batal" class="btn btn-danger fa fa-ban"></button>
        </form>

        <?php
        if (!$_SESSION['nama_user1']) 
        {
        echo "<script language='JavaScript'> 
            alert('Anda sudah pernah mengisi sebelumnya');
            document.location='index.php';
            </script>";
        } 
        else {
              $_SESSION['kirim_jawaban'] = false;

        error_reporting(0);
        $nama_dosen = $_POST['nama_dosen'];
        $matkul = $_POST['matkul'];
        $semester = $_POST['semester'];
        $jenis_pertanyaan = $_POST['jenis_pertanyaan'];
        $pertanyaan = $_POST['pertanyaan'];
        $bobot = $_POST['bobot'];
        $nama_mhs = $_POST['nama_mhs'];

        $jumlah_dipilih = count($nama_dosen);
        $jumlah_dipilih = count($matkul);
        $jumlah_dipilih = count($semester);
        $jumlah_dipilih = count($jenis_pertanyaan);
        $jumlah_dipilih = count($pertanyaan);
        $jumlah_dipilih = count($bobot);
        $jumlah_dipilih = count($nama_mhs);
        
        for($x=0;$x<$jumlah_dipilih;$x++){
            mysqli_query($db, "INSERT INTO tb_penilaian values('','$nama_dosen[$x]','$matkul[$x]','$semester[$x]','$jenis_pertanyaan[$x]','$pertanyaan[$x]','$bobot[$x]','$nama_mhs[$x]')") or die ($db->error);
        }
           echo "<script language='JavaScript'> 
            alert('Data Berhasil di Kirim');
            document.location='sem1.php';
            </script>";
        ?>

image.png

Buat join table dr table tb_matkul ke tb_penilaian dr sini akan dapat flag apakah tb_penilaian exists atau tidak, gunakan ternary jika exists show button pilih, jika tidak disabled button