Side effects cannot be anticipated. If any develop or change in intensity, inform your doctor as soon as possible. Only your doctor can determine if it is safe for you to continue taking Wellbutrin.

Side effects of Wellbutrin may include:
Agitation, constipation, dizziness, dry mouth, excessive sweating, headache, nausea, vomiting, skin rash, sleep disturbances, tremor

Side effects of Wellbutrin SR may include:
Agitation, constipation, dizziness, dry mouth, insomnia, nausea, rash, sweating, weight loss

Side effects of Wellbutrin XL may include:
Abdominal pain, agitation, anxiety, constipation, diarrhea, dizziness, dry mouth, heart palpitations, increased urination, insomnia, muscle soreness, nausea, rash, ringing in the ears, sore throat, sweating

http://www.drugs.com/pdr/wellbutrin-xl.html

Maybe it's "agitation" of a sort. Do you experience dry mouth? Maybe you were just trying to wet your lips or something?