The first change I suggested was for your error: model.fc, I am assuming you fixed that by changing to model.classifier.
coming to my second suggestion. you are getting the following error because you are trying to include the parameters in the optimizer where requires_grad = False. So, I suggested you to filter out those parameters by applying filter function.
ValueError: optimizing a parameter that doesn't require gradients

I think these were your concerns in the original post. As you are getting a very high batch loss. Can you please add more details like batch size ? Also, I see that you are using a pretrained model and finetuning. S0, why don’t you start with a lower learning rate like 0.0001 ?
Also, how does the loss change as you progress ? Does it decrease or very unstable ? If yes, can you show some values ?