I adopted a ball python a few months ago from a friend of mine. My friend had acquired him from another person that was not taking very good care of him and she had previous reptile experience and got him to where he can be handled again. The first month I had him, everything was great. He was very curious and adorable and would crawl all over the living room and loved to be held (well, I assume he did, he didn't seem to mind). The person that gave him to me had supplied me with some food but mentioned she had bought the wrong one and normally fed him something bigger.
One night while I was thawing his tiny meal, some boxes and things fell off my closet shelf which is only about three feet from his cage. When I got him out to feed him, he bit me. It completely freaked me out and ever since I have been getting him out with a wire hanger and not handling him at all.
I have since started feeding him larger mice that are more suitable to his size. I think that part of his lashing out was that he had been underfed for a long time and then was stressed by the vibrations of the falling boxes.

My major question is: How can I tell if he is ready to start being handled again?

Also, any other tips and tricks for getting the little guy back to his "puppy-like" self again are greatly appreciated.