I agree, I picked this up from long term accutane use so I know that tablets can basically wipe out all your natural good bacteria which in turn messes up your immune system and loads of other things.
One thing you guys can try if you think it may be some sort of bacteria or fungal infection is steam your lips using boiling water with a few drops of tea tree oil in, that would do no harm and could potentially help clear any infections etc.
I would really try not to use tablets long term though if possible its not great for the body.