How Can A Knuckle Tear With Lumps, Itching And Pus Be Treated?

I cut my knuckle 6 months ago, it was a flap of skin that I tried to heal with first aid cream. It looked healed but discolored. A week ago started to itch and it became red with bumps filled with pus. I put an antibiotic on but it looks worse now. What do I do? Thank you in advance for your response.