Will my receding gums return to normal?

In the past year, I have noticed my gum receding on my lower front teeth. My dentist says my gums are healthy, so there is no risk of the tooth falling out. I was told it was due to my brushing technique - I effectively dragged the gum away from the tooth. My hygienist at the dentist told me to flick the brush upwards to help with the problem, but my regular dentist says it will never come back to normal. Is this true? I don't trust my dentist since she tends to be very blunt and unhelpful. Is it possible for the gum to regrow?