1 – Drinking water will help your dry skin.
It doesn’t. Drinking water is important to stay hydrated, but if you have dry skin you need to water the outside of your skin, not the inside. Drinking lots of water no more moisturizes your skin than taking a bath quenches your thirst.
2 – Sunscreens with sun protection factor (SPF) of 100 are twice as good as sunscreens with SPF of 50.
As you can see from the graph, there are large differences in sunscreen protection at low SPF; however, there is not much difference in protection once the SPF is at least 30, which is what most dermatologists recommend.
3 – Sweating will make my acne worse.
Sweating does not make acne worse — in fact, sweat is your natural antibiotic. Keeping tight, wet gym clothes on after a workout can clog your pores which can flare acne. So can too much sun. Cover up. Go for a run. Shower. (And if you live in the southeast in August, shower again).
Did you already know these? What skin question would you like answered? Comment here or ask me on Twitter @Dermdoc