With a melt like that. You should trim and replant the tops of your stems. You're typically not going to get growth out of those bottoms again. Every once in a while you will, but I think you're best to just trim it,and not rely on hopes of what night not happen. Lol
I am Rowdaddy.
20L Convict "Bedroom"
1.5gal in progress
55 gal Paludarium/Vivarium coming soon
I get side shoots out the yingyang when I leave the bottom trimmed portions in the tank and replant the tops elsewhere. It is the way to get very thick busy stands of stems. Trim and let the side shoots grow, then trim the side shoots and you can double sometimes quadruple your stems in a very short time. There are some stems that do not like to be trimmed, but most LOVE to be trimmed.
Lower leaves developing holes can be a potassium deficiency. Try doubling up for a week to see if it stops. Old leaves will not recover! My stems needed more magnesium, when I dose 3 tsp after each water change in my 200 gallon system they are healthier. I did that on a hunch after increasing flow and bumping CO2 did nothing good. My GH ought to be fine but a bit more was better. Increasing the hours the lights were on was another experiment that succeeded. Keep track of how much you are dosing and change one thing at a time to see what happens. It can happen quickly as you have already noticed.
I am with you Kathyy