Our son's DID fill back in, but if you google it, some people never regain the tissue (some scary stories out there). We give DS all-over body lotion every night after his bath, and we made it a part of the routine to massage the area particularly well each night. This is what our doctor suggested, and DH (the usual lotion-spreader) had already been doing it when we received the recommendation.
We just went to our regular doctor - a family doctor. It was his office that had administered the shot. He noted it in the record and said that he/we would be very cautious about doing a steroid injection again, should he ever really need it. I think since then DS has NOT needed a steroid injection for wheezing. We have his wheezing pretty much under control by avoiding foods that he is sensitive to. One thing about getting those injections is that they need to be placed correctly (not sure where - IN the muscle tissue? rather than BETWEEN muscle and fat??), and this is difficult to do on a child - even more difficult if your child is thin.