I had Kybella injections 48hrs ago, can I still use Retin A before going to sleep?

Retin A can be quite irritating to the skin, so if you are still tender or sore from the Kybella injections, I’d avoid using Retin-A there. However, you can use it on the rest of your face and neck. Once your skin feels less tender, feel free to use the Retin A under your chin as well. It won’t affect your Kybella treatment at all. Consulting a board-certified dermatologist for your Kybella will give you the best chance of beautiful results.

You needn't be concerned. The tiny openings from the needle used for your Kybella treatments have closed by now, and you can apply Retin-A. However, because your skin is somewhat inflamed, you may want to use it less frequently than previously, perhaps every three or four nights, until you see whether or not it irritates your skin. All the best!  Dr. Clark

Kybella should have no effect on the surface of the skin so using Retin A after treatment is fine and won't cause a problem with your treatment.