Hello Aspirant,

See it is not recommended to have Mehandi on hand while giving such examinations but as you already have it on your hand so don't worry you will only have to give your thumb impression there on the attendance sheet.

As per the guidelines for examination day of JEE:-

>>>> You should carry your Admit card along with one government ID proof.

>>>> Masks are compulsory in the wake of pandemic.

>>>> There you will have to maintain the distance of at least 6 feet.

>>>> When you will enter in the examination hall you will have to give your left hand thumb impression on attendance sheet.

For more detailed guidelines kindly check out the link given below :-

https://engineering.careers360.com/articles/jee-main-exam-day-guidelines

I hope you got it.

All The Best for your Examination :))