pH at 7.2 is not to low- 7.2 to 7.8 is the good range (so 7.2 is the low end, but not excessive)
The tabs will gradually add Cl and CYA as they dissolve, continue to monitor FC and add bleach to maintain your Cl levels
Your pH should rise over time, but watch it- the trichlor (the pucks are trichlor) can cause it to go down- so you may need to use some borax initially to boost it/keep it above 7.2.
Once the CYA is in, you should quit using the tabs and the pH will start to rise...
you can add the baking soda if nothing else, but it doesn't add as much pH as borax and will also increase TA more...
not sure about the skin burning- may be just the dry skin getting acclimated, but may be something in water- the chlorine will kill it if its something in the water