PUPPP?

Initially my OBGYN thought I had PUPPP but when I in to see her, she said it's not and my skin condition is from stretchmarks. Her reason for it not being PUPPP is because it's not all over my body. It's just on my abdomen but I also have intense itchiness on both my knees and the inside of my thighs! I've been showering with Grandpa's Pine Tar soap and per her recommendation been slathering my abdomen with Neutrogena Sesame Body Oil. It helps a little but the itchiness comes back! I can't stand it!
I'm currently 36 weeks... Any ideas?