[Miko]

The situation of your hammy is not that complicated but it can be if not taken to vet because the age is increasing and risks increase too. The teeth problems are very common ,you may not see it but he may be suffering from pain yk. Rapid increase in his activities is probably due to the pain I guess, as he may do such things to divert himself. I've experienced it that some hamsters just sleep all the time in pain but some become active. So we can't just judge acc to the behavior. I'd prefer to remove harsh objects from his cage and give him soft foods like homemade applesauce or mashed/boiled veggies. And if you're wondering that hamsters go mentally ill, They will be stressed due to health issues but mentally ill is not a case. Keep an eye on him and I hope he will be back to normal very soon.