Hello Adraadhi

Yes you can do MBBS after BAMS but then again you will have to give NEET and crack that to get into MBBS colleges and then  study for 5.5 years before you get a degree so that will waste a lot of your time it's better that you keep you focus and goal on MBBS right after 12th so you will end up saving a lot of your time.

hope this helps you