If polycystic ovarian disease is left untreated, will it become worse and do more harm to my body? tried losing weight but it doesn't help

No harm: Pcos doesn't always need treated. You may have difficulty getting pregnant when you are ready, but it can be treated then.

Depends: Pcos accompanied with a lack of a menstrual cycle may lead to a build up of the uterine lining which may become abnormal over time. Periodic shedding of the uterine lining is a good idea. Loosing weight by sticking with a complex carbohydrate, low glycemic index, diet along with moderate exercising will help you tremendously in the long run. Syndrome x may be a concern as one ages.