jekyll and mr. hyde, it changes me. it changes me.es me like a monster. >> me, i did like terrible, horrible, horrible thing to my son. because of the drug. >> sanchez has been charged with serious bodily injury to a child. she admits to being high on heroin, and severely beating her 3-year-old son. when he was brought to the hospital, he was covered in bruises, had bite marks on his thigh, and one eye was swollen shut. doctors also discovered he had a lacerated liver, likely caused by blunt force trauma. >> when i am high on heroin, it is like anything triggers me. i'll just go off. i mean, i could be sitting next to someone. if some little thing irritate me, i'll start screaming, i mean, like on attack mode. it's -- it is scary. basically, i chose that drug over my kids. and they probably have a better life without me. >> sanchez's son has recovered, and is living with relatives. if convicted in trial, sanchez could face anywhere from five to 99 years in prison. but she is working with prosecutors on a plea deal. she says the only w