Seeing your personal info 15 years.
STD infections are rare.. still STD if you suspect i would advice you take a general body check up too.. white lesion in upper lip may be because of hundreds of reasons.
Vitamin deficiencies, lichen planus like infection fungal infection etc etc not necessarily STD white lesions more than 3 weeks in mouth needs to be checked ASAP. Instead of curious visit oral surgeon SOON
Next Steps
Also have a general body check up with a physician