Yep. He can never use it again, unless he gets another curse mark from orochimaru.
Karin by itself isn't actually a jutsu, he just causes thunderstorms and manipulates the thunder into striking a location.
How does he do it? Well he uses a "Fire Element:Great dragon fire technique" which causes the atmospheres temperature to change in the area causing a lightning storm among the clouds.
My theory is that he can never use it again due to not having the chakra to do it without using the second level of the curse, due to the fact that he does not use it until he changes into that form, even after Itachi removes it
See look he is out of it
then next page he has it on
Uses the Jutsu
Then next time he is seen his mark is wearing off