Validation Loss too high

Thiru: <pre><code class="lang-auto">def train(epoch,model,device,optimizer,loss_fn,dataloader):
   model.train()
   running_loss = 0.0
   pbar = tqdm(enumerate(dataloader),total=len(dataloader))
   for i,(img,label) in pbar:
       opt.zero_grad()
       img = img.to(device).float()
       label = label.to(device).float()
       with torch.cuda.amp.autocast():
           logits = model(img)
           loss = loss_fn(logits.flatten(),label)
           running_loss += loss.item() * img.size(0)
       scaler.scale(loss).backward()
       scaler.step(optimizer)
       scaler.update()
   Epoch_Loss = running_loss/len(dataloader)
   writer.add_scalar("Loss/TrainEpoch",Epoch_Loss,epoch)
   print(f"Epoch:{epoch} TrainLoss:{Epoch_Loss}")
   return Epoch_Loss


def val(epoch,device,model,loss_fn,dataloader):
    model.eval()
    running_loss=0.0
    pbar = tqdm(enumerate(dataloader),total=len(dataloader))
    for i,(img,label) in pbar:
        img = img.to(device).float()
        label = label.to(device).float()
        with torch.no_grad():
            outputs = model(img)
            loss = loss_fn(outputs.flatten(),label)
            running_loss += loss.item() * img.size(0)
            try:
                auc = roc_auc_score(y_true=label.cpu(),y_score=outputs.sigmoid().cpu())
            except ValueError as e:
                error=e
    Epoch_Loss = running_loss/len(dataloader)
    writer.add_scalar("Loss/ValEpoch",Epoch_Loss,epoch)
    print(f"Epoch: {epoch} Validation Loss: {Epoch_Loss}")
    return Epoch_Loss

</code></pre>
<p>This is my training and validation loop</p>
<p>Model: Efficientnet B3<br>
Loss: BCEWithLogits<br>
Dataset: Melanoma2020+Melanoma2019 (Highly Imbalanced 85.6% negative samples and just 14.4% positive samples)<br>
optimizer: Adam(lr=0.001,weight_decay=1e-6)<br>
lr_scheduler: ReduceLROnPlateau()<br>
folds: GroupKFold(splits=6)</p>
<p><div class="lightbox-wrapper"><a class="lightbox" href="https://discuss.pytorch.org/uploads/default/original/3X/1/d/1d3b17422f2cf83a0725e9520a1e7a7235c23ea5.png" data-download-href="https://discuss.pytorch.org/uploads/default/1d3b17422f2cf83a0725e9520a1e7a7235c23ea5" title="Screenshot from 2021-01-18 09-35-35"><img src="https://discuss.pytorch.org/uploads/default/optimized/3X/1/d/1d3b17422f2cf83a0725e9520a1e7a7235c23ea5_2_689x335.png" alt="Screenshot from 2021-01-18 09-35-35" data-base62-sha1="4aArMVIVpg7boWHKyj0tkVmyUFD" width="689" height="335" srcset="https://discuss.pytorch.org/uploads/default/optimized/3X/1/d/1d3b17422f2cf83a0725e9520a1e7a7235c23ea5_2_689x335.png, https://discuss.pytorch.org/uploads/default/optimized/3X/1/d/1d3b17422f2cf83a0725e9520a1e7a7235c23ea5_2_1033x502.png 1.5x, https://discuss.pytorch.org/uploads/default/original/3X/1/d/1d3b17422f2cf83a0725e9520a1e7a7235c23ea5.png 2x" data-dominant-color="4F5251"><div class="meta"><svg class="fa d-icon d-icon-far-image svg-icon" aria-hidden="true"><use href="#far-image"></use></svg><span class="filename">Screenshot from 2021-01-18 09-35-35</span><span class="informations">1344×654 82.1 KB</span><svg class="fa d-icon d-icon-discourse-expand svg-icon" aria-hidden="true"><use href="#discourse-expand"></use></svg></div></a></div></p>
<p>These are my model and other configs, My validation loss is going too high like 214. I wanna know that is there any mistake with my training and validation loop or just tuning my hyper parameters will do. I couldn’t find any improvement in the model. Any help will be appreciated.</p>
<p>Thanks in Advance</p>