I doubt its barry in the mask, simply because hunter was obsessed with going faster after taking the velocity 6 which ultimately was killing him, he was dying because of taking so much of it. Only absorbing true speedforce from another speedster was the only way to cure him.
the question is does zoom have his speed plus barry's speed on top of that, because zoom was way faster than barry without the tachyon device, so whether zoom absorbs the speed that would make him faster or was it just absorbing the speed force to heal him....flashes speed plus zooms speed would mean barry would be a turtle compared to zoom, the writers sometimes leave things cut and dry with no explanation.
like the tachyon device, so barry can't naturally get faster, the way i took it was he can only go faster by wearing a device, that's kind of lame.
or does he have to wear it for awhile and then it allows him to store more speed force thus making his speed permanently faster....the guy in the mask is definitely not black so its not wally west...and the hair looks almost dirty blonde, i think its jay garrick, but the real good one, maybe from another earth....in the comics jay garrick was the slowest version of the flash so maybe zoom caught him, took his speed, then used velocity 6 a bunch of times, got sick and realized he needed the flashes speed to cure himself...all i know is they need to find a way for barry to learn to get faster if he's going to face zoom again or anyone with that caliber of speed, the person in the mask will probably be revealed in the final episode of season 2, leaving it to continue for season 3.
https://en.wikipedia.org/wiki/Trajectory_(DC_Comics)