Mature Male Rose Hair.

I got my Male Rosie about three weeks ago. The lady told me he was actually a female but he has those mating hooks. She had no idea how old he is either. At the time, I knew nothing about them and I still don't know much. I read that they're not suppose to molt after maturity but Saatana looks like he's about to molt. His abdomen has a bald spot, he's not as active as usual and he hasn't eaten for about a week. Should I worry??

Sometimes mature males will stop eating and focus primarily on finding a mate. Mature males do not live for very long after maturity. Mature males CAN molt after maturity, is called postultimate, though I don't know how rare or common this is as I've never seen it myself.

Aw, this is horrible! v.v
Thank you, though!

Mature males will live varying lengths of time after their maturing molt. Some will attempt and achieve a post ultimate molt, but that is rare. I had two Aphonopelma burica males live just shy of a year after maturation. Both died attempting a post-ultimate molt, but continued to eat weekly up until their demise. My OBT male lived for 18 months post maturation, but only took food every month or so. I've heard of a couple of G. rosea males living 3 and 4 years after maturity.

Bald spots are not indicative of an impending molt, just that the spider has been kicking hairs.

Roseas have been reported to fast for up to 2 years. Not eating for a week is nothing. As was already mentioned, some males forgo food in hopes of finding a mate.