Oh wow. have you been formally diagnosed with OCD and if so, have you had any treatment whatsoever?
Hello, along with my staring OCD I am germaphobic also, I try very hard not to use public transportation because of it but when I have to I wash my hands clothes and shoes with pine and bleach along with washing my hands repeatedly I won't eat or touch anything for hours until I talk myself into it. Washing and sanitizing makes me happy and calm. But in your case with touching your mouth, I would freak out also, that would be major for me. Try wringing with mouthwash or baking soda and peroxide to sterilize your mouth. I sometimes brush with that, but be Sure not to swallow at all. Talking to a therapist would help. I tell myself that my body will protect me and nothing lasts forever even germs. Take care it will pass.