If you are hurting yourself to bring calm into your life then yes it is absolutely worth seeking a therapist. And the fact that you feel stable most of the other time outside the self-harming periods is good in that, a lot of good therapy can be done while you're feeling stable. If you were in constant crisis mode a therapist would be in a more supporting role and any deep therapy would need to be held off until you're more stable.

I would suggest if you have any deep trauma in your past, that you find a suitably qualified therapist. One who deals with trauma, self injury, abuse etc because your college one may not be and even if they are, if i'm correct, they'll only be available to you during term and not after graduation. It will be better to have someone who isn't affected by these rules.