Whenever I have high toxicity and have the toxicity face and use Aard Piercing Cold, the face immediately becomes normal until I reload the save. From what I know this has been going on since piercing cold was released. This is really annoying and I haven't found a fix for this yet.
A similar mod was released a while ago that fixes a bug where Quen removes the toxicity face when it breaks or goes away ( https://www.nexusmod...cher3/mods/2349 ). According to its description it adds an automatic check to reset the face toxicity when the quen shield goes away. Could the same idea be used but it checks whenever you use piercing cold?