My 8mth DS has sucked his thumb since he was 5 mths old. His poor little thumb has a permanent callous and the skin is raw. To promote healing of his thumb, I put a mutt on his hand, but this only aggravated him. Should I leave well enough alone and let him use his thumb for comfort? Or should I intervene and attempt to wean him off it? If so, how should I go about doing this?