my western hognose that i purchased a couple months ago has stopped eating... it has refused pinkies for the last 3 weeks... ive tried once a week

it used to eat fine, i fed it about 3-4x without any trouble eating. now its like it gets upset when i try to give him a pinky... it just hisses and puffs at it, but doesnt seem interested...

when should i start worrying? its very small (8-10 inches) so i dont want it to miss too many feedings...

any ideas on what i could do?