I just did a Happy Dance for Jackson!
After more thought: (scary) He more than likely built up antibodies against Lymes by having the disease, so vaccinating him wouldn't be necessary. You could do a titer instead. I have heard alot of flaky stuff going on with Lymes, like a lot of false positives when pets/people are tested, and vaccines that really don't provide the protection they were developed for.
Jackson's turn around is truly amazing! I can't stop thinking about it. I wouldn't worry about his weight loss at this point, but do keep an eye on it, maybe weekly would be good. I'm sure as soon as his activity level picks up, so will his appetite. He doesn't look thin, and from his videos he looks very fit and healthy. Good job Mommy.