Firstly I wouldn’t recommend kissing your guinea pigs, for your sake and for your pigs.
I personally wouldn’t want to share bacteria with someone who eats poop
Secondly, is there a chance you are allergic to the pigs? Do you have any reaction anywhere else when you clean their cage out/touch them?
I would recommend always washing your hands thoroughly after cleaning/cuddling, this is what I do as I have a minor allergy to them and I find this helps keep it under control. It’s also just good practice!
And although I know it’s hard, perhaps stop the cuddles, or atleast keep your pigs away from your face. You can always have lap time and cuddles, but maybe from now on you have to do so away from your face.