What Causes A Rash On The Lower Lip Line?

hi, for some months i have had this rash on my lower lip/lip line. It feels like a colsore but isnt, its incredibly itchy then flaky, comes and gos but mostly all the time now. My doctor tjhought it might be angular chelitis so i had a blood test and while my iron levels were on the low side i'm not clinically anemic. So i have been to a dermatoligist, and a biopsy was taken of my lip but what is bothering me is that trouble isnt on my lip but rather the lip line. The dermatoligist thought it is solar keratoses(?) and i have had heaps of sun exposure working outdoors and a keen sailor and surfer as well so thats a fair call but it still worries me cause its like not my actual lip but the skin immediatly next to it ...what do you think