I have reported this. MRPG is full of bugs at the moment. If you assign all the skills and points then go back to the main game and back to MRPG, your HP will be back to normal.
For me, I don't gain XP at all at the moment, but that may be due to being a considerably higher level than you. It's worth checking if you are gaining XP at the moment. If you aren't, there's obviously no reason to play MRPG until the bugs are fixed.