ANSWER:

Yes, it is a major sin and punishable in hell. 

https://islamqa.info/en/answers/112659/will-allaah-punish-women-who-make-a-wanton-display-of-their-beauty-tabarruj

Is covering the head is awrah for a woman? If she doesn’t cover and reveal her hair in front of non mahram men, is it a major sin? What is the severity and punishment for it according to the Quran and Sunnah?

Beautification & Cosmetic Suregry, Women clothing | September 10, 2019 9:48 pm
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So the awrah under the chin or the lower chin is awrah. I cover it up but it is extremely hard because my scarf keeps slipping and during prayer I keep trying to fix it and I can’t have KHUSU Because of it, it’s jusy a small area. Can I just leave it, please explain ?