yes it will affect the flowers. they suck the life giving saps out of the leaves. your plant will stop growing and eventually die unless you do somthing.
Yep, spider mites. Sorry bro, that blows. I've read that the best things to do when they're into bloom is to spray the leaves with water each day to keep them under control, but personally, I don't like the idea because you'll be risking bud mold. I never had to deal with spider mites, myself, but I'd hit them with a heavy dose of neem oil, which will suffocate some of the little bastards. It's also safe to use during bloom, so that might be an option.
That's just my 'two cents', so I'd wait and see if anybody with more experience chimes in, as there may be better solutions.