Hello
Thanks for the query to H.C.M. Forum.
Your 
dermatologist prescribed stieva , sun screen and face wash . You can use these cream , gel till you didn't  find out the root cause of acne and obesity .
In my opinion the reason of acne , obesity , dark coloration may be due to .
1 
Hormonal imbalance , as  these symptoms are very common due to change of certain hormones . Diagnosis can be confirmed by blood examination of estrogen, androgen , F SH/LH ratio.
2 Poly Cystic 
Ovarian Disease or PCOD is the most common cause of obesity , acne , dark coloration in child bearing age group female ( 18 years are most prone ).
3 Excessive spicy or greasy or fatty foods are also responsible for acne and obesity , so avoid these foods.
After rule out of these above mentioned reasons take following treatment . 
Wash face with lukewarm water , dry it with towel , don't RUB.
Now wash with KETOLITE soap . dry with towel .
Apply Glyaha-koj lotion twice in day  at least for one month. 
Also take 
clindamycin or 
erythromycin tablets ( OTC ) orally for 10 days.
Good luck 
Dr. HET