[2021] So....what now?

All purchasable content of Stranger Things will be removed, if you got anything before the date and time, you will keep it.

If you are not able to obtain it beforehand, they'll be gone for good after the 17th November.

Here's a FAQ to everything: https://forum.deadbydaylight.com/en/kb/articles/292-f-a-q-stranger-things-last-chance-sale

Originally posted by jmoyano92: and what about the blood clothes when you level up the character?

Yes, you can still prestige ST characters if you own them.