Hello, I read carefully your query and understand your concern. You may have an epidermoid cyst if the bump on your knee doesn t form a head and continues to grow in size. Epidermoid cysts are usually slow-growing. They appear as a small bump without a white bump. In case that they get infected, they can turn in red. I suggest using anti inflammatory medications such as Acetaminophen to relieve the inflammation. I also recommend using an antibiotic cream for local application. Hope my answer was helpful. If you have further queries feel free to contact me again. Kind regards! Dr.Dorina Gurabardhi General &Family Physician