How long has he been like that? How is his walking? Is he dragging his bottom? You most likely will need to take him into the veterinarian to get better medication. Until you can get him in and if he was mine, I'd start by doing the following:
I'd start by using white fleece bedding to monitor for color (blood to see if its bleeding or if he's dragging his butt around), urine spots (size, number of spots & color of urine), etc. Remove the clumping litter, I don't recommend it at all. I know of a couple a couple of decades ago now who used it until it got stuck to private areas and caused blockage (penile sheath). I'd also keep it clean, pat it dry with some gauze and using a tiny amount neosprin for now.