I have red veins on the apples of my cheeks and melasma on my cheekbones, so they merge together in a big patch :( Can a treatment like laser or IPL be done at the same time?

Hmm, sympathies. Get yourself in front of a great practitioner and get their opinion on where to start with this. They may prefer to get you on a specific skincare protocol for melasma and get a handle on this before diving in with a laser. Get an expert opinion and see what they say.