There are many things that can cause bumps on the penis and the best way to identify what is going on in your case is to see your doctor
One cause of small red bumps is an infection/irritation of the hair follicles called folliculitis, which can occur after shaving. These will typically go away on their own and can be helped by applying warm wash clothes, but can also develop into an abscess
that needs to be drained. Some infections will also require antibiotics and it is important to see your doctor to determine whether you have a collection that needs antibiotics or drainage.
Other penile lesions can be caused by a yeast infection, a sexually transmitted disease, a drug reaction, genital warts, scabies, skin inflammation such as eczema
, and, rarely, by skin cancers. You should make sure to see a doctor even sooner if you develop swelling of your penis or start to notice oozing of foul-smelling liquid, if you are unable to retract your foreskin (if you are uncircumcised), and if you have systemic symptoms including fevers, chills, joint aches, swollen or painful glands, mouth sores, sore throat, malaise or fatigue. You should go see your doctor to have the lesions examined and for further diagnostic testing and further referral if necessary.