To see if your weight got updated you could use the following scheme:
# Save init values
old_state_dict = {}
for key in model.state_dict():
old_state_dict[key] = model.state_dict()[key].clone()

# Your training procedure
...

# Save new params
new_state_dict = {}
for key in model.state_dict():
    new_state_dict[key] = model.state_dict()[key].clone()

# Compare params
for key in old_state_dict:
    if not (old_state_dict[key] == new_state_dict[key]).all():
        print('Diff in {}'.format(key))

Let’s see, if the weight updates are just small or not happening.