Change MOS in active duty army?

Your MOS is an under strength MOS. When it's time to reenlist you can request a new MOS. I would advise against anything else medical if you ever want to get promoted. Most of them require you are a non promotable E4. Several require college you probably don't have. Several are always over strength. Most do not ever have training available. Don't bother with waiting for 68B, E, F, G, P, or T.
68W is your best choice for career progression and offers the most openings into other medical fields once you get education. 68V is good once you have the college credits because they accept E5. 68L, N, K, Q, and U all require college.
Bottom line, if you're in the medical field you are progressing without college.

Talk to your retention. They would have a better answer for you than random people on the internet.

Things you need to research are the different medical MOS there maybe some you may not know exists as some don’t work directly in the hospital setting ie 68R, 68T, 68S. There are great opportunities although one thing to keep in mind is the overall strength of that MOS as it will determine if you’re even able to reclass. You also need to know the difference between ST and GT scores because some medical MOS require a certain score from either or to be able to reclass into. Along with talking to your Retention NCO, it’s best to get a grasp of the actual job by speaking to friends in different medical MOS to see what they actually do and the opportunities they have for advancement so you can tan truly ask yourself if you’d enjoy it. All in all, don’t just settle, choose something you want to do for the long run.