I have heard co co butter or shea butter
Don't scratch you will get stretch marks. I use vitamin e ointment and it works
Try not to scratch what ive used with all my children is anything outmeal. When your itchy take a oatmeal bayh in,warm water not hot because hot water drys your skin. I uses baby johnson in johnson oatmeal lotion it helps too. I habe 6 kids and hardly any stretch marks at all. None on my bell at all just a couple of light ones on my sides.
Try either Sarna sensitive or Sarna menthol. They've helped me tremendously and I have PUPPP. Oatmeal baths dnt work for me at all. You might even try soaking in Epsom salts then rubbing the sarna on the belly.
I bought some organic non ichy soap n use coco butter to stop the itching