I cannot add too much to the responses that you've already received as they are all on point. In answer to a second part of your question: yes, often times your disease can develop more symptoms over time. Especially if one does not take their medication and/or if one does not make the appropriate lifestyle changes in order to avoid flare-ups or worsening of the disease.
As has been said, Lupus is different for each of us and it comes in many forms. Some of us have very few symptoms and others are virtually bedridden due to numerous symptoms.
While Lupus may not cause the deformities of RA, the symptoms (pain, nerve damage, inflammation) can be so severe as to make the use of your hands impossible. So, the potential for all AI diseases to cause life altering changes are all equally great.
Like you, music is my life. As such, I do everything in my power to ensure that I can continue with my passion for as long as I can. I am absolutely serious about taking all of my medications, I exercise regularly (regardless of pain, exhaustion, fatigue, etc.), I eat healthy, I avoid all things that could exacerbate the disease or cause a flare up, and I make sure that I allow my body to rest when it needs to. Trying to achieve some form of normalcy with this disease is a full time job and we must be diligent in that job..especially if we are pursuing something that it important to us.
Now, that is not to say that many of us have not had to defer our dreams or had to re-examine our dreams, or even had to build new dreams. It is important to know that all of these are possible and none of these are life ending. Many of us have decided that our most important dream is to be healthy and happy and that there are many things that can and will make us happy.
I do wish you the very best in everything that you do and I hope that this illness does not prevent you from finding your happiness.
Peace and Blessings
Look For The Good and Praise It!