Dear Hot glue?
It has been my experience that hot glue will come off readily from a
"textured" block wall much more reliably than from a flat, painted wall. The
paint our district has used on our sheet rock walls will come off with the
hot glue. You may LUCK out and have quality paint that will not come off.
Keep your fingers crossed and your paint swatches ready.
Have Fun,
LaDonna
Way down south in Columbia, SC