Second time getting botox, will I see improvement or it will be as the first time?

When treated within six months one can expect an slight cumulative effect of the two treatments. If there is an asymmetry in muscle mass that is something that can be reduced by adjusting the Botox dose left versus right, even to compensate for asymmetric chewing. You can even ask your doctor to treat only one side. 

Hi msitu,It is hard to discuss your case without seeing photos. That said, how much Botox was injected into the hypertrophied (bigger) side? Definitely, more should have been injected into that area and less on the weaker side.Results will vary depending on how much was given and the masseter muscle status at the time of injection.All the best, Justin Harper, M.D.