Box dye allergy test

[Cwcwbird]

It's been a while since I used a box dye. I've done the allergy test but it says I have to leave it on for 48 hours. How risky is it to only leave it on for say 12 or 24 hours?? I wash my hair every day because I run or go to the gym every day. I'd rather not skip a run but I also don't want to be one of those people you hear about with swollen faces and hair falling out...

I did a lot of allergy tests for box dye during lockdown as I didn't fancy having to go to A&E! Anyone I did one on the back of my wrist for eyebrow tint and all was fine for first 24 or so hours then by 48 hours it slightly blistered.

I've never had a problem before and impossible to tell what would have happened if I'd gone ahead on brows after 24 hours (different skin sensitivity) but I was a bit startled and now always cautious

They say 48 hours for a reason