Looks like you have developed a Sebaceous Cyst
A sebaceous cyst is a closed sac under the skin filled with a cheese-like or oily material.
Sebaceous cysts most often arise from swollen hair follicles. Skin trauma
can also induce a cyst to form.These cysts are usually found on the face, neck, and trunk. They are usually slow- growing, painless, freely movable lumps beneath the skin. Occasionally, however, a cyst will become inflamed and tender.
The main symptom is usually a small, non-painful lump beneath the skin.
If the lump becomes infected or inflammed, other symptoms may include:
Tender or sore skin
Warm skin in the affected area
Grayish-white, cheesy, foul-smelling material may drain from the cyst.
Sebaceous cysts generally do not require medical treatment. However, if they continue to grow, they may become unsightly, painful, infected, or all of the above, then a surgical excision can be done which is a simple procedure to completely remove the sac and its contents.
Hope it helps
Dr Geetika Paul