If you’ve had chicken pox before and have had mysterious pain/tingling on an arm/leg on the same side of the body as those for the past few days it could be shingles
I just had it at 33 last week and it looked very similar to that when it first popped up





Stomach acid is like 10,000,000x more acidic than most alkaline water is basic. Dilution is probably doing an order of magnitude more work than the hydroxide here (meaning just drink more tap water)