Maybe you have build up from the heat protectant you used? Silicones make my hair straighter and less defined, I had a few horrible lank weeks recently from an accidental silicone. That and mineral oil could be locking moisture out of your hair, you can clarify with cocoamidopropyl betaine you don't have to sulphate.
It's always a good idea to have a trim after damage is caused. Could also try a coconut oil deep treatment? Are you really using hairspray on top of little to no conditioner? Hairspray can be quite damaging.