heya, when i was 22 i had an abnormal smear result so went back for another, that came back abnormal too (the cells were pre-cancerous and had gotten worse in 3 months). i had to go to the gynecological unit at our hospital where they did a biopsy - it is similar to a smear but took longer.
if they decide to do one you can get anesthetic. they use a speculum and you have your feet in stirrups (or you did at mine as you are in that position for a little while). if they say they are going to do that then make sure you wriggle and get comfy as you can't wriggle while they are doing it. it feels like a really intense period pain or a contraction, but just in your womb/ovaries, the soreness goes away almost as soon as they are finished.
after that i had to have what is called a 'colposcopy', so i went back and they did this - i will admit it was sore and i had period pains for a couple of weeks afterwards plus a lot of discharge/bleeding - this is because they use a laser to remove the top layer of cells, the ones which have gone bad.
i have been all clear since and have yearly smears which have all been fine. it wasn't pleasant at the time, but all the staff know you are in a horrible position and are really kind and patient. take some paracetamol with your and some sanitary towels as if they want to do a biopsy the hospital towels are horrid!
it's most likely that they will just have a look, they are experts so might know what is going on just by having a look, or they might give you an appointment to come back for treatment. if you have questions to ask try writing them down today and taking them as you will forget while you are in xxx