is an important indicator of many disease groups and conditions that should be taken seriously. I would not treat this indicator as something "that should be brought back to normal with a medicine".
ESR is mainly elevated in three types of conditions: infection, inflammation in autoimmune diseases and malignancies. I do not want to load you with information that might be out of the scope of interest for a non-medical person, but if somebody has an autoimmune disease and receives antibiotics, ESR can temporarily decrease (just like in your case).
So, I would advise you to go back to your doctor and have a through discussion about this. Depending on your age, sex as well as some other factors, you might have certain conditions that you should be tested for. Discuss them with your doctor and ask him/her to refer you for appropriate tests.
In my personal opinion, considering your previous hip pain
, muscle pain
and elevated ESR, I would think about some kind of autoimmune condition.
Hope this helps.