Hi,
Are there other symptoms present? A sebaceous cyst is a closed sac or cyst below the surface of the skin which may affect the scalp, ears, back, face,and may occur anywhere on the body except the palms of the hands and soles of the feet. They are smooth to the touch, vary in size, and are generally round in shape. This may be caused by blocked sebaceous glands, swollen hair follicles, and excessive testosterone production. If they continue to grow, they may become unsightly, painful, or infected. Surgical excision of a sebaceous cyst is a simple procedure to completely remove the sac and its contents. An infected cyst may require oral antibiotics or other treatment before and/or after excision.
I would recommend that you have this evaluated further by your doctor for proper management. Direct clinical examination of the cyst will help determine the treatment suited for you. Warm compress or over-the-counter pain medications may help. Try to avoid manipulating the lesion. Take care and keep us posted.
My stepson had one of these cysts, his was a sebaceous cyst that had to be surgically removed. It hasn't come back since.