Pimples or acne
is more found in the face, back, and even arms. Pimples can form in the penis but it is not as common as on the face. Though the skin lesion on on the penis can appear as a pimple, it is also suspicious for other medical conditions such as chlamydia as you mentioned. It is not very common to have a lesion on the penis that produces a lot of pus, and even leading to pain on urination (dysuria). He should make an appointment with his primary care doctor
to have it examined. They might collected some urine and swab the area for the sample. The important thing to rule out at this point is a sexually transmitted disease (STD
). If it is positive for a STD, it could be treated with antibiotics if it is bacterial in origin. Other STD's that it could be could also be herpes. Syphillus is also possible. Even though you two were tested and are in a relationship, you should also have an open mind to the idea that your partner could be having sex with other people. To protect yourself from STDs, you should have protected sex, with a male or female condom. Again, it is important to speak with a primary care doctor.