Have Cut On Index Finger. Taken Antibiotics. Red Lump On Joint, Pain. Need Another Doctor

I deeply cut the inside of my index finger joint 2 1/2 months ago with a filet knife while cleaning fish. I cleaned it well kept it taped and cleaned and it healed fine in a week. 4 wks later a large red lump developed on the very top of my joint not exactly where I cut it. It hurts terribly, it throbs and wakes me at night. I went to minor er and they gave me antibiotics. It persisted and I went to regular md she said it needed to be drained and sent me to a hand surgeon. He said it was just still healing and should get better in a few wks that scars get worse before they get better. This was at the 7 wk mark. I m miserable and want someone to do something. I cannot flex the finger past half way but I can extend it fully. My finger is allittles swollen but no severe. Should I just wait it out or find another hand surgeon. He took x-rays but said an infection could only be confirmed by an MRI or bone scan. Expensive tests I m hoping to avoid.