I have a red spot , kind of shiny, the size of the tip of marker mabye, and it stays there for a month or 2 , on head of penis under foreskin?

Several things: The most common cause of such a spot would be a rash called lichen planus or maybe psoriasis. You should see a dermatologist for an accurate diagnosis. The doctor might also want to rule out sexually transmitted infections.

Difficult to know: At your age a recurring but resolving lesion on the glans may be nothing to worry about. However, this is something that has to be looked at to know. It could require nothing or a topical medication but could require further testing and even a biopsy. No reason to risk a problem. Get it checked out by your pcp, a urologist or a dermatologist.