Oh gosh, I feel for you, PUPPP is really rough, especially when it flares up at night! From what I've heard, the itching can be managed depending on how bad yours is. Some mums swear by topical steroids prescribed by their doctor to calm the inflammation down, while others have found relief with cooler compresses or even keeping the area really dry and loose clothing. My friend actually went to her ob-gyn at Mount Elizabeth and they gave her a mild steroid cream plus antihistamines, and she said it made a huge difference within a week or two.
For the stretch marks underneath, once the PUPPP settles, the Mama's Choice Stretchmark Cream and Serum are really good, pregnancy-safe and a lot of us have found they do help with texture and appearance over time. But honestly, your priority right now is getting that itch under control first, it's miserable otherwise!
Definitely check in with your doctor or specialist about this though, as they can assess how severe it is and prescribe what's safest for you at your stage of pregnancy. Hang in there!