Natalie, Some facetious and serious tips:
1. Regarding nail care: I find that gnawing on mine suffices. Occasionally I gnaw too far but it has never stopped me from playing.
2. Regarding hand and finger care (and arm as well). I have suffered from tendonitis in my left arm, frozen shoulder, "trigger finger" in both thumbs and my 3rd valve ("ring") finger and I broke two bones in my right hand last year a day prior to a recording session. Make sure you have a really good orthopedist who specializes in hand care and that he/she refers you to a good occupational therapist who knows how to work with musicians. A general orthopedist who specializes in sports injuries may not be as sensitive to the fine motor issues that musicians have as needed.
3. After a mixed experience with the local orthopedist with my first trigger finger surgery, I asked a friend with the Boston Symphony for a referral and was ultimately directed to Hand Surgery, PC in Newton, MA. by Doug Yeo. Dr. Matthew Leibman is my hand specialist. Dr. Leibman is the "go to" specialist for the Red Sox, Patriots, Bruins, and various members of the BSO. While I don't fit in with that crowd, he treats me with the same care they get, and it is very good indeed.
4. My Occupational Therapist is with my local hospital and is more convenient. She is very good at working out exercise programs to help with finger, hand, and lower arm problems. Once you get to shoulder, back, and other body parts, you get referred to physical therapists.
That is my experience.
Doug
Adams E3 0.60 Sterling bell - Prototype top sprung valves
Concord Band
Winchendon Winds
Townsend Military Band