Clipped these lettuce leaves off my 26 day old plant. Is this edible?
I’m so sorry, but your lettuce is infested with thrips. Those white areas and black spots show that the damage is already done by thrips. As you zoom in you see pale long bodies that are thrip nymphs that are ready to infest other plants.
I would recommend throwing those plants away asap and clean the garden and surfaces around it carefully.
You will find more tips on how to fight thrips in this forum, just use the keywords for search.