Young leaves rolled and distorted could be either chemical damage or Rhododendron Gall Midge, Clinodiplosis rhododendri, which are 3 or 4 times larger than a grain of Salt. The rhododendron gall midge is a tiny insect that feeds in the spring and causes distorted leaves to emerge. There is no way to undo the damage once it has occurred. Chemical damage should be associated with a chemical application (fertilizer, herbicide, deicing salt, etc.) and should affect more than one plant.

Here is a link that might be useful: How to grow rhododendrons and azaleas.