Very oily yet very dry skin

Hi my name is Sonia. I'm 16 years old and I've been struggling with various acne problems for a while now.
I've been seeing a dermatologist, but I try to find alternate remedies as well (since prescriptions tend to be very expensive)
Right now, I've been using Differin and Duac acne lotions. I've been on those for maybe 2 years.
Lately, however, my skin has been VERY dry (seeing as it's winter in Minnesota). But at the same time, I have extremely oily skin, which I usually blot once every hour (but I don't need to as much lately).
So I'm very confused as to why my skin is very oily yet very dry at the same time. I use cetaphil to wash, olay to moisturize, and sometimes even olive oil as a moisturizer (I heard it's a good natural product).
Oh and one more question on the side: is it bad to be using a body moisturizer on your face? I usually use a facial moisturizer, but I have this body lotion that works fairly well, and I thought I should give it a chance on my face.

Any help on my situation would be greatly appreciated :)

[loiloi]

Hi. I recommend products made especially for oily acneic skin which has become dry or fragilised due to acne treatments such as Differin and Duac. La Roche-Posay make a cleanser called Effaclar H (not the regular Effaclar which is just for oily skin). Lutsine Hydrafnia make a cleanser and moisturiser especially for this problem. Look online at pharmamudi and parasend sites if you can't get them in stores near you.
Use an oil-free moisturiser on your face. Olive oil and body lotions are likely to be too greasy and block your pores.
Eloise.