Okay what size of tank is mojo in? what size of tank is she in now? those stripes are stress stripes. Something is stressing her out badly. It isn't healthy but also depending on her size I had it happen with my store bought bettas but after a while and figuring out what was stressing them, the stripes went away. What is the environment her tank is around right now or in?
America (f, HM), Spirit (m, DBLT), Rescue (f, VT), Missile (m, HM), Purnurple (m, HMPK), Dragon (m, VT), platies, mollies, sorority tank of 21 females, AND lots of guppies.