Is there any posibility for the pupila to be rebuilt if this it was damaged after an cataracta surge?

Pupilloplasty. Yes, surgical pupilloplasty is possible if the tissues are not extremely damaged. A corneal specialist should be familiar with this procedure.
Usually yes. It depends on the amount and type of damage, but there are several ways of correcting damage to the iris to repair the pupil.
Video Iris repair. http://www.youtube.com/watch?v=z89zr171xri&feature=youtube_gdata_player.
Yes. There are many options for a damaged iris/pupil after cataract surgery: suture used to repair defect is called pupilloplasty; artificial iris (an implant put behind or in front of remaining iris to make pupil look normal; corneal tattoo (least invasive and fewer risks of eye infection getting into the eye: used purely for cosmetic look as will not fix iris). .
May be hard to do. The colored part of the eye that makes the pupil is called the iris. The iris is thin and soft, so repairing it may be hard to do. Sometimes, repairs are done for people with traumatic eyeball injuries or people born with part of the iris missing. One can get some opinions from eye surgeons who do such repairs, to get an idea about whether or not one's problem is fixable.