I hope your hamster is better now! And once my friend put one of those "Primapore" bandages over her ham's bald spot. A few weeks later it grew back! And the bandage wasn't painful since it was the "Primapore" kind. The adhesive is really quite mild. You might have some difficulty trimming the plaster to fit the hamster's bald spot though... It took us an hour and several bandages to get the fit right!