Glycolic Acid, AHA, BHA, PHA, HUH?

[Summer]

Okay, let me get this straight.

Glycolic Acid is a pure form of AHA?

Salicylic Acid is BHA (are there other forms of BHA??)

BHA penetrates the pores AHA just affects the top layer?

I thought I read BHA is for dry skin, but now I am reading it's best for oily skin.

AHA is too strong for dry skin, is this true?

I have read that BHA reverses sun damage but will make your skin 50% more sensitive to the sun. Is this true?

Now I read that PHA is the best for dry skin. Acts like an AHA, but gentler.

What products have PHA ( Poly Hydroxy Acid)in it? I never heard of it until a few days ago.

I don't know, what should I be using if any? I have dry sensitive skin with some blackheads on my nose. Manual exfoliation isn't helping.

All I use is a cleanser and moisturizer and sometimes s/s. I know, I need to get into the habit.

Any advice on what I should be using would be greatly appreciated.

thanks in advance!