Anxiety is a bugger, isn't it? I do it and now I hav like a darker bit on my lower lip where I have bit it so much. But if someone was going to kiss you, if should be for the right reasons and not just because your lip looks different ffrom where you've chewed it.
My sister and I do this. But I usually bite the top part just the center top. My lips always stay soft. LOL it is normal. try putting something nasty on your lip. Something you do not like the taste of.