Strange n now not eating

My snake for the alst four days has not been his self he keeps out of his hides and is either crawling up the side of the tank or on his tree with his head straight up. It is not a new tank temps are normal (90 hot spot 83 Ambient) and now hes just stopped eating. He has never missed a meal before so any advice would be fine and dandy thanks!!!!

He could be looking for a female if he's old enough, that's what I'd put my money on.

Just double check his mouth and nostrils to ensure you don't see any bubbles or mucus to rule out an RI