I Scraped My Knee And Took A Chunk Of My

I scraped my knee and took a chunk of my skin of and then proceeded to accidentally scrape my knee once again on the same spot on the same day. then about a week later i managed to scrape my knee once more and the healing scab came off. its been about 4 months and some white pimple like bumps have formed as the scab continued to heal. Why is this happening? Is it a problem? will they go away?