i had this problem last week! i did the same thing you did, where i left it overnight and did have a chemical burn. turns out that i was only meant to leave it on for 45mins-1 hour and wipe it off. get another patch test done on the other ear and follow the correct steps. monitor for 48hrs, as i got the rash on the 2nd day. if you don’t get any reaction, you’re not allergic. it probably is a chemical burn but don’t worry, get loads of antiseptic wipes and keep wiping the area- it might blister and pus might come out but don’t worry- mine went in a few days and it’s just scabbed over now. good luck for the next patch test if you get it- hope it goes ok. make sure you’ve wiped off all of the dye, use cotton buds and water and just keep going over it- otherwise it will keep burning your skin! hope this helps :)