You don't mention how often you are receiving acupuncture, just that you have been going for 4 months. It sounds like the acupuncture is helping your condition and that it is somewhat long-standing. A long term prognosis is almost impossible to offer without knowing what your TCM diagnosis is (not the western one), what points are being used, the level of change, etc. It is certainly with the realm of possibility to require treatment for 6 months to a year for long-standing conditions of this nature. This may be weekly, bi-weekly, monthly, and this will depend on your overall level of response and the style/methodology your practitioner follows.
What does your current practitioner think? What type of prognosis have they offered?