I get these pea-sized boil like things in my pelvic region. They are very painful to touch and they come often. They are pus and blood filled. They leave marks if I squeeze them. I have shaved the region in the past. I have been getting these pimples ever since I was 11 (I'm 14 now). However, before shaving, they went away without marks. Please help as I don't want any scars.
It sounds like you have and infection in your skin. Given how long you have had it, I would recommend that you see a dermatologist (a skin doctor) for treatment. I would also strongly advise you to stop shaving your pubic hair. It isn't necessary and shaving creates nicks in the skin which allows bacteria to settle into the area. In other words, the more you shave the more you spread the problem.
Let your hair grow out. If you want to trim the hairs to keep them shorter than normal, that is fine so long as you are not cutting them all the way down to the skin. It will itch badly for about a week as the hairs begin growing out, but it will calm down once the hairs have come out.
Other things you can do is wash daily. This will cut down on the amount of germs on the surface of your skin. Avoid squeezing the pimples because that can drive the bacteria deeper into your skin. Also make sure you change your underwear daily. You definitely don't want to put the same pair of underwear back on after bathing -- you will just put the bacteria back on your skin that you just scrubbed off. Wear something different at night, such as pajamas without underwear.
Antibiotic ointment might work initially. The problem is most ointments are oily, so while they kill the bacteria, the oils tend to clog up your pores, which something you don't need. You can try it for three days, applying the ointment twice a day, to see if it makes it better or not.