Hi, A Month Ago I Developed A Painful Growth Inside

Hi, a month ago I developed a painful growth inside my hand, on the front of the knuckle. It has gotten bigger and more painful, and I actually have an apt to have it looked at in 20 min at Urgent Care. An hour ago, I felt a dull pain building in my inner forearm, half way up, and when I looked, I saw a pea-sized protrusion had appeared. I ran my finger over it and then gently pressed it with my finger and the thing disappeared. I have a dull ache in my forearm. I currently am taking Warfarin for a DVT, ankle to groin, right leg, and have had Antiphospholipid Antibody Syndrome for 3 years now. Do you know what the forearm thing could be? Thanks! Erin