Bathe for no more than 10 minutes at a time, no more than once per day, in warm water. Use moisturizing soaps or no soap at all. Pat dry and use a moisturizer immediately after drying to lock in any residual bathing moisture. You can use any moisturizing lotion or even baby oil or petroleum jelly.
To treat cellulite, your best options are an alpha hydroxy lotion to remove the dry skin that makes cellulite look worse & a self tanner to make it less noticeable. The creams and lotions that claim to treat cellulite may diminish the puckering a bit for a few hours but, none have significant long term results.
Dermatologists can treat cellulite with suction, laser, light, and/or radio frequency treatments. But, they don't eliminate the problem and must be repeated often. $$$$