What is this

skin Irritation and sharp pain but its on and off. i have had sex encounters but i used protection and i just noticed now idk how long they been there

underneath the head of the penis

and 21

What Stick has observed could well be right - the frenulum is what some men refer to as 'the banjo string' and your actual string looks like it was removed when you were circumcised. Although you do have some 'frenular skin' attachment from the top of your penile shaft onto the underneath of your glans / head of penis.

However, the red bumps you are talking about are the site of two different glands - these are Tysons and Parafrenular Glands. In some men they are very distinctive, in others they are not visable at all - what I think you have is one of these particular kinds of glands that are slightly visable.

Therefore, I think you have a combination of things going on: you have glands that you can see, but this would not be the cause of pain unless you severely irritated them, such as scratching or picking at them with a fingernail.

So, the pain sensation is likely to be caused by something else: this could be anything from a bladder infection, a urinary tract infection or an infection of your meatus (your pee-hole) - only, you are associating the pain with the head area of your penis.

You could potentially have internal damage to your penis, but this is unlikely unless you have put severe pressure on your penis, or have had sustained rough sex, or something like that .......

How long have you had the sensation of pain?

i had picked with it because i though it was a pimple but about a month almost

Okay, so here is a logical sequence for you: obviously do not pick at the red bumps again as these are Glands of one of types I mentioned. Then ...

You could try applying some antiseptic cream once a day, or every other day after you have taken a shower, for a bout a week or 10 days to see if the sensation of pain diminishes. Certainly if the sensation of pain is not fading away within another 2 or 3 weeks you need to start to suspect that the source of the pain is being caused by something other that the irritated glands. You may need to seek professional medical advice if the pain sensation persists. Also ...

Get in the habit of not directly applying soap or shower gel and stuff like that to clean your penis and when taking a shower - simply rinse-away any bodily cleansers that have reached your penis when taking a shower with plain water and rub with the inside of your hand. When you wash your penis other than when taking a shower, again, use water only - and as you currently have irritated glands, be careful not to irritate them when drying your penis with a towel.

Once the sensation of pain has resolved itself get some liquid Coconut Oil and apply a light film of this to your entire penile skin - 2 or 3 times a week is sufficient, best time to do this is after you have taken a shower and throughly dried yourself .....