The most likely explanation isn't that they're scorched, but short of water - these shrubs cope well with full sun in the ground, so perhaps it needs a bigger pot if its been in the same one for a couple of years or more. If its got more root room and fresh compost, it should hold more water within the pot, but in full sun (when there is any) it will need a good soaking daily or every other day. Check also for mildew - these plants are prone to it, and that can make the leaves shrivel and curl.

yes, I agree with Bamboo. I have 2 of these in a south facing garden [not in pots] and they look great at the moment, in flower and can take heat.