Aw mama, PUPPP is really tough, one of my mum friends had it around the same weeks and she was miserable din! Since you're already on antihistamines and it's spreading after a week, I'd really suggest checking with your OB kasi sometimes kailangan ng topical steroids or additional treatment to stop it from getting worse (especially na malapit mo nang ma-deliver). A few of us found na loose, soft cotton clothing and avoiding hot showers helped a bit sa itching, but honestly your doctor would know best kung ano ang safe pa for you at baby at gaano na kalaki ang spread, don't tough it out, mama, you deserve to feel better before labor!