You can't get std from a dog that way. The dogs mouth doesn't have std's. Maybe some bacteria and you should wash your hands after a dog puts their mouth on you in general. But your worry about std's are unwarranted. Not a risk for those.
Nobody is dumb here. Questions are how people learn. STD's do not jump species and humans will not get an std from a dog's mouth. That's the point. Again, wash your hands before touching yourself or putting your hands in your mouth or anything like that if your dog licks you. That's just good hygiene. And if you find you worry about things a lot like this, I'd consider looking into anxiety.