Patch of fur missing

Hi, my sugar baby, Gobbles, has about a 1" patch of fur missing on the top of his forearm - maybe it fell out or he licked it off or it feel out? Could this be from FD or perhaps his insulin (lantus)? He was diagnosied 10 days ago and has been on Lantus for 6 days.
Any input would be greatly appreciated

 

I've never heard of hair loss caused by diabetes, unless it's stress-related, maybe? My cat Mikey has had a microscopic missing patch of hair over his left shoulder since forever (I first noticed it when he was about 10 weeks old). There are all sorts of causes for hair loss that the vet checked him for (for free :mrgreen: ) and they concluded it was a simple scar. It might help to know that the most common cause is usually a cat being a cat and getting into who knows what kind of mischief. Second most common is ringworm (which is easily treatable).

 

It's not from where the vet shaved a bit of fur off to draw blood is it? That's the right place

 

I think it is....cause the vet tech took Gobbles in the back room to draw blood...now I feel dumb....I should of thought od that....Thanks!