Need some good advice

Not sure if this has anything to do with it, but I checked tonight and it looks like he had a double shed over night. I know it sounds strange but I check all my snakes every night and spot clean at the same time. And I swear to you it was a double shed.....

Don't force feed him. Force feeding really shouldn't be used other than with hatchlings that haven't absorbed their yoke. Assist feeding is an option, but IMO, only if the snake has lost about half it's body weight. Your snake could lose a lot of weight before I would worry about him. If he is constricting it, then leave him alone next time you feed him. Don't look at him, don't check on him, nothing. Put the prey in, wait for him to strike and coil, then shut of the lights, walk out the door, and don't look back for several hours.

I would just be patient. If he made it to 542 he was eating well at some point, especially if he was eating hopper mice. My thought is that with it coming in to breeding season it's possible if temps were dropped on him he went into breeding mode and went off feed for the season. This could especially be true if somehow he was introduced. None of my males have gone off yet, but my temps are still up. I purchased a female pin one time in feb advertised at 800g. She came in at 900g, but didn't eat for me for till the following may. I was a nervous wreck even though everyone told me to be patient. When the next breeding season came along she did the same thing even though she didn't breed. And now this year she hasn't gone off feed yet, but she is starting to get hit and miss again. I've personally never had a snake that small go off feed, but so I can't say how it'll handle it, but a snake that's 1000g that goes off feed for the breeding season will still end up around 925 or higher by the time it goes back on feed. So I would imagine you guy can handle a little fasting. Just keep good husbandry, offer food every week, be patient and confident wait it out. If may comes around and he doesn't eat or if he loses more than 20% of his body weight that's when you want to get worried and seek out a vet. As for killing but not eating its always been explained to me like this. And I feel would hold true especially if the snake was used to eating live. The snake is healthy enough to defend itself, but not hungry enough to eat. If the snake is stressed out enough to not eat, it will more than likely go into flight rather than fight. Striking is good. Just interested in other things than eating right now.

WOOOHOOOO thanks everyone he ate today. And my mistake everyone, I meant assist feed not force feed. I did have to assist him because he was trying to eat a leg and getting stuck. I held the mouse after he killed it and sort of directed the head to his mouth and he did the rest. Thank-you to everyone my stress level has dropped in a big big way.