We are not doctors and cannot diagnose rashes. However, I would suspect that if it were a problem with something going on in the pool, which is unlikely, it would be much more widespread. Probably best to see your doctor if it continues.

Test strips are horrible at reading CYA levels. Go ahead and order the kit on Friday so you will have the ability to test properly and get good readings. Since your pool has only been filled for a few weeks, I doubt that your CYA is too high yet so using dichlor or bleach would be ok.

You are using products that we don't support and that can be risky. Most algaecides should not be used. I know nothing about the one you mention but am skeptical about it. The only algaecide we recommend is Polyquat 60% but even that is not routinely needed. If your pH goes too low, instead of using pH rise, you can just use 20 Mule Team Borax (laundry aisle at Walmart).