I noticed a white dot that shows up on my penis after masturbation. Then it fades away after some hours. I'm freaking out just noticed it like 2 ago?

Probably nothing... Probably not abnormal. For sure not an STD. Something that comes and goes like this might be related to blood flow, which is increased with sexual arousal. If so, penile skin may have more color, highlighting a pale spot ("white dot"). Maybe just a small area of vitiligo (reduced skin pigment), prominent sebaceous gland, fibroma, etc. See a doctor if still worried or other spots appear.