If you lose a lot of weight rapidly the skin is inevitable. There are some foods that you can eat to help out high cellulose and anti aging content vegetables aide in healthy skin: chard, dandelion, kale, celery, carrots and ginger. Your best bet is to blend them into a smoothie so you can eat a lot at once. Raw coco butter and almond oil rubbed directly on your skin helps with elasticity and hydration drink a lot of water.These measures will make a small difference but generally the skin has already been damaged from being stretched and it will wrinkle and sag when it's no longer being extended. Invest in supportive undergarments like Spanex to control, bulges and folds of skin. But most of all love yourself and be grateful you have the skin folds to remind you how far you've come to a healthier you!
I agree that if you lost a lot of weight rapidly or if you've been overweight for an extended period, the skin is inevitable. I'm not sure there's anything you can do for cellulite, but drinking water and staying hydrated will help.
I also believe that exercise will help keep you toned, which might help camouflage the skin issue.
Staying hydrated and overly moisturized can help bounce your skin back to normal quicker!
I use coconut oil and CereVe cream, but that's just my preference : )
Good luck!