My BP thinks I'm food! :(

Get a snake hook, just a small one. Gently touch your snake on the top of the head before you reach down just to knock him out of feeding mode. If needed, use the hook to drag the snake into a position where you can reach from behind, rather than putting your hand straight at its face.

I think it's been said, but I'll say it again... I don't think your snake is mistaking you for food, I think your snake has "forgotten" who you are, in that it thinks you are going to eat it. It's scared!

I had a snake like yours, that was kept in a pet store for a year. She was born feisty, and the shop owner didn't think he'd have her long so didn't bother handling her. Mind you, she's a corn snake but still.
I used to get bit COUNTLESS times while taking her out. After about 2 weeks I thought I couldn't do it. I talked to a breeder in the states, however, and she gave me some good advice that really worked.

What I did was, I took my snake out every day for a 5 days out of the week (apart from feeding day and 2 days following); and I did this for 2 weeks. I had her out for 1-2 hours at a time, and just sat with her. I watched TV with her in my arms/lap/whatever. If she bit me, I either took it or put on gloves. I wouldn't put her back until she was calm and collected. After not even the full 2 weeks, completely different snake. It's like something clicked in her brain and she realized I wasn't interested in eating her. It's been almost a full year since then, and I haven't been bit again.

All the best!

Make sure hes well fed every 10 days or so. After that just use a snake hook to remove him from his cage and he should calm down. Most likely just a food response. Ball pythons are usually very very tame and placid, especially as they get older.