OK, this small lump apeared on my shoulder during a time i was clean, I know I shot b-12 there, it's been 2 months and hasn't really got any bigger but it does bother me a little. What the hell is it? I did stick a slin pin in it and nothing came out. Maybe I didn't go deep enough. Any ideas? I have some augmentin xr that I was going to take but don't know the dosages and duration that it should be taken for. HELP!