Middle center of bottom Lip has become darken and slight itchy??

[pgh412dude]

Lips have become dark and scabby when dry for about 3 wks now.  I have medicated lip balm and HPlecern and been using for about a week.  When I am out in sun and for get to put chapstick with spf my lips are dry and itchy for the next few days, howerever this time it has become dark and scabby on top and bottom lips in the center.  I played Volleyball for a couple hours about 2 weeks ago.  So I'm thinking this isn't related to being in the sun.  I'm dealing with yeast infection and psoriasis issues on my body/groin area as well.  Could this be related? HELP..Pharmacist told me to use a little Neosporin on it for a few days and see what happens, if no change see a Derm which I had an appointment and he said just plain Vaseline..although the Neosporin don't seem to help, I would think something else on the medicated side would help!  Never had issues with my lips so this is hella embarrassing and do not know what to do??  .  Didn't blister or bump up so he thinks its not a cold sore by the way it looks.  Slightly itchy at times just dark and if I don't put chapstick on it for a little while it will scab up and get really dry.  Any ideas????  Any doctors out there??