Hello and hope you are doing well.
It looks like an abscess. It could also be a sebaceous cyst, a lipoma, or lymph nodes. It could also be due to allergic reactions and infected hair follicles. If there is accompanying swelling, redness, discharge and fever it is most probably an infection. You may need to consult your primary care physician who will examine you and initiate appropriate therapy.
Hope this helped and do keep us posted.
In my opinion it looks like a Sebaceous Cyst.
I would recommend seeing a Dermatologist about this.