I've had a small hard pea size bump next to the head of my penis on the foreskin, 3 years ago I had oral sex and the bump has been there 3 weeks now?

Bump. Common things are common and this lesion may have nothing to do with your sexual activity, but it is best to see help with a family physician or dermatologist to best diagnose and treat your concern.
May be just a cyst? Is this bump just seen for 3 weeks? Does it hurt? What is its size (by mm)? Is there any raw surface on this bump? So, collect the feature, degree, and progress of the symptom and sign over time with their detailed sequence of events, bring those to doc for analysis, review, history, physicals, and tests as needed so he/she may deduce what it's and how and when to deal with it if needed. Best...