try some savlon (make sure not to get any inside) to make it go away.
the tender redness is obviously irritation of some kind which he gets from your hands and mouth, try using some soft hand cream on your hands throughout the day before you tug on his salami

also try washing your hands before, a shower or bath is good. cover all the angles. change your toothpaste, might have a dodgy reaction - doubt it tho, never heard of someone being allergic to toothpaste :P
leave it for a couple of days, if it persists have your man go to a doctor for a checkup.
that's how i would approach the situation if i were in your bf's shoes, so to speak.
hope this helps.
regards,
Sebastien