Hello and hope you are doing well.
Your symptoms could be an allergic reaction to the pills. They do not appear to be FDA approved. FDA (Food and Drug Administration) the controlling authority for all medications. If you see all the OTC's and some herbal medications will not have their approval. This is important because, it means that no scientific studies have been conducted for these medications hence interaction with other medications or their side effects would not have been studied. There are a lot of safe medications approved for control of obesity, hence opt for safer therapy.
Hope this helped and do keep us posted.
It's quite possible it could be a reaction to the pill. Perhaps you should stop taking it to see if it goes away without the slimquick. If they're from the pill then these spots are hives. I personally have had very good results at getting rid of or lessening the time of having hives using benedryl. However my hives are a define allergic reaction which is why the antihistamine helps.
However, have you already had the chicken pox? Have you been around any young sick children or anyone with the chicken pox? This can include people at a dr's office (because some parent's don't realize how contagious they are).
I think until you figure out the cause, all you can do is try to curb the symptoms- use calamine lotion to help sooth the itchy skin.