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.
Oh wow. have you been formally diagnosed with OCD and if so, have you had any treatment whatsoever?