Hi there! Thanks so much for this question. Carboxy for circles around the eyes is absolutely brilliant! However, it has to be done SO precisely! If your therapists does not watch where the gas runs and does not block the appropriate areas when doing the treatment, yes, there can be some pressure on the sinuses making it really uncomfortable for sinus sufferers. So to answer your question, yes, carboxy therapy done incorrectly can put pressure on your sinuses.