Hello,
A clinical examination is very important for accurate diagnosis and treatment. Most of the bumps on penis are normal. Other fairly common condition is infection of the sebaceous glands or simply pimple like growths. Razor bumps or follicultis can also cause bumps on the penis.Avoid scratching them as it can lead to infection and scarring. Apply a topical antibiotic like Bacitracin, polysporin or triple antibiotic ointment. If the symptoms are severe get it seen by a dermatologist. I sincerely hope it helps.
Take care and regards!