First off, it’s really better NOT to pop things on your penis with a pin or needle (or anything else, really). This can sometimes cause an infection. It’s much better to let a doctor handle anything like that, so that you can be sure it’s done in a sterile and safe manner. Temporary bumps and lumps of the sort you describe are not uncommon; the penis skin, as you know, is elastic and stretchy and also clumps up. Sometimes these lumps form under the skin as a result of rough penis handling (and other reasons) and go away on their own. If one persists, let your doctor know. On a general note, regularly use a top notch penis health cream (health professionals recommend Man1 Man Oil) for general penis health. A cream that includes alpha lipoic acid, a superior antioxidant, can help to keep penis skin looking healthier.