Which is correct:
1 Let me know what grade you have gotten when the teacher tells you.
2 Let me know what grade you get when the teacher tells you.
There are two possible cases,
a The teacher has corrected the paper but has not yet told 'you' what grade 'you' had obtained (the grade has already been obtained)
b The teacher has not corrected the paper yet and no grade has been obtained.
I am not sure whether in each of these cases a different tense will be chosen or not.
The speaker probably does not know whether a or b is the case. Therefore there is no reason to prefer one tense over the other. But I still prefer 2 over 1. For one thing, it is natural everywhere in the English speaking world, while "gotten" is used only in North America. But the main reason for my preference is that 2 sounds more natural to me than 1.