I have two six year old cats, brother and sister (friend "forgot" to fix their parents, so I know the specific litter and birth date). The female keeps scratching her chin profusely, to the point that she bleeds. I seriously doubt this is acne because the black dots are scabbing up and there is blood. I have not taken her to a DVM yet because I would like to see if there is something simple (and cheap) I can try without incurring vet bills. I am not asking for medical advice. Ideally, there would be something simple such as "slip a vitamin or something into her food" that I could try first: maybe her skin is dry and a supplement will help. The dog gets supplements to help his skin/fur, but dogs and cats are different so I am not sure what to do.
The male has no scratching problem. Sure, he scratches himself like any cat does. However, his sister goes to town on her chin, sitting there scratching until she bleeds: I have had to soak bed sheets to get the stains out when she does this on our bed.
Daily diet for both cats combined: 5.5 oz Friskies Savory Shreds, 1/2 cup Core Wellness Grain-Free. I chose the food, my DVM instructed me this is a good quantity based on their combined weight and the fact it is almost impossible to feed two cats separately.
Update: I took her to a vet allergist who performed an allergy test. She is allergic to dust mites, which are practically impossible to eliminate from a home. While veterinary specialists can be expensive, it is a worthwhile investment for any other pet owners who are faced with a similar issue.