 The study team will use non-invasive skin probes to perform daily assessments of transepidermal water loss TEWL and skin pH. TEWL will be measured using the DermaLab TEWL probe Cortex Technology, Hadsund, Dermark, which consists of an open probe with paired sensors placed at different distances from the skin. Humidity and temperature are measured in each sensor to calculate vapor pressure gradients. The difference between two vapor pressure gradient measures is representative of TEWL at that point on the skin 19, 20. Environmental humidity levels will also be measured using the DermaLab before obtaining the TEWL measures. The average humidity readings from the two sensors will be recorded as environmental humidity. The probe will be thoroughly cleaned with 70 ethanol prior to and between uses to minimize cross-contamination or microbial transmission. The ethanol will be allowed to air dry prior to use of the probe. The Extech PH100 meter will be used to measure skin pH in the range of 0.00 to 14.00. The small flat surface electrode provides a non-intrusive accurate measure of pH. No Sting will be reapplied on day seven. 