Don't listen to that for a minute. Dont give up, know your are valuable beyond your skin. Your skin will get better but be consistent with whatever method you use or it won't work . Try and listen to videos about lifting your self worth because your value is not in your skin..

Do you have family history of acne? Have you tried consulting an obgyn inorder to work you up on other conditions like pcos. Or an internist, sometimes acne is just a symptom of an underlying disease. Its just good to rule out underlying diseases, so your treatment will be more targeted to the main problem. I know first hand how damaging acne to self esteem is, it helps to be in this community. Youll realize youre not alone in this fight. I always tell myself i can still walk and see while others dont. Im still somewhat lucky

Sorry if this comes off the wrong way, but your parents are assholes. Aren't they suppose to support you? I really don't understand why they would be so insensitive and put you down.

I suggest making another trip to the dermatologist, telling him/her all the things that haven't worked, and ask for accutane.

Sorry for what your mom said to you, that's really nasty. She should be there to listen to you instead of blaming you for something you can't control 

Have you tried cutting out dairy products? It didn't clear my acne, but it helped a little, and I've heard many people say it improved their skin a lot. So that's a first change you could try to make.

Also definitely see a dermatologist if possible cause OTC products might not suit everyone.

Cheers.