If this is the only available treatment for your condition, you may be allowed to use them on a temporary basis until such time the condition improves. But instead of you applying the procedure, let your husband do it: In this way you can guard against the sin of self-stimulation. Having said this, I must reiterate that you ought to refrain from it as soon as you are able to establish normal intercourse.

As for ghusl, you definitely need to perform it, as long as it has resulted in orgasm.