14 Year Old Son Has What I Think Is A

14 year old son has what I think is a paroxysmal finger hematoma on the tip of left index finger swollen out 3/8 of an inch. Initially would not stop bleeding before the swelling began a week ago. Before the swelling it looked like a small blood blister beneath the skin and eventually began bleeding without stopping. Was cauterized be pediatrician the the swelling began....Looking for a course of treatment. He also has Ulcerative Colitus and is in between his 2nd and 3rd treatments of remecaid. Finger symptoms began before initial remecaid treatment.