Zinc deficiency can also affect the skin, as can an essential fatty acid deficiency. And many B-vitamins have cracked lips as a deficiency symptom, so you may need to find a good multi-vitamin or B-complex supplement to take just so you aren't missing something important.
Some medications can affect the skin as well, so you might want to discuss your meds with your pharmacist and your doctors to see what they think.
Chronic Lyme Disease, Gluten & Sulfite Sensitivity, Many Food/Inhalant/Medication/Chemical Allergies & Intolerances, Asthma, Gut issues (dysmotility, non-specific inflammation), UCTD ("Secondary Lupus-Like Syndrome"), Osteoporosis, Pancytopenia, chronic malabsorption/malnutrition, etc.; G Tube; Currently TPN-dependent.
Meds: Zofran, Pulmicort, Heparin (to flush PICC line), IV Ceftazidime (for Pleural Effusion).