Here's a link to some white colored hair wax that I've used for costumes before. It does a pretty good job.
https://www.ebay.com/p/Mofajang-Hair-White-Wax-Temporary-Hairstyle-Cream-Pomades-for-Men-and-Women/2016527833?iid=183106287280&chn=ps&ul_ref=https%253A%252F%252Frover.ebay.com%252Frover%252F1%252F711-117182-37290-0%252F2%253Fmpre%253Dhttps%25253A%25252F%25252Fwww.ebay.com%25252Fp%25252FMofajang-Hair-White-Wax-Temporary-Hairstyle-Cream-Pomades-for-Men-and-Women%25252F2016527833%25253Fiid%25253D183106287280%252526chn%25253Dps%2526itemid%253D183106287280%2526targetid%253D412885918683%2526device%253Dm%2526adtype%253Dpla%2526googleloc%253D9014961%2526poi%253D%2526campaignid%253D1425762668%2526adgroupid%253D54746042863%2526rlsatarget%253Dpla-412885918683%2526abcId%253D1139066%2526merchantid%253D115299274%2526gclid%253DCj0KCQjwof3cBRD9ARIsAP8x70O6Rp_ELea2Kt9MsmkJ41iQXhNfzVZVHpR9tKpK686ajE151fpN2l4aAmbzEALw_wcB%2526srcrot%253D711-117182-37290-0%2526rvr_id%253D1671125258098%2526rvr_ts%253De7bf1cbc1650ad4cccd43927fff6c7f6