Good afternoon dr am 18 weeks pregnant and usually use hairdryer dry my private part to avoid any infection.usually i do everyday 5-8 mins can it cause harm but today i feelhigh temperature in my private area.can it cause harm to baby or air embolism?

This sort of thing does not prevent infections of any kind. For sure you must not place the opening at your vagina, i.e. to inflate your vagina with air, cold or hot. That could indeed be damaging; never do it. If it feels good to blow warm air over your genital area, that's fine -- but perhaps not on a high heat setting. But don't fool yourself; it doesn't improve genital health in any way.