If a woman exposes awrah to another woman, what is invalid?

If a woman uncovers or exposes her awrah (private part) to another woman because of a medical procedure (example laser hair removal in the private parts), is it sinful? What does this act invalidate? Does it make prayer invalid? For how long does it make prayer invalid? Does it invalidate wudu? What else should I know? I have to get laser hair removal twice a year in the private part (and rest of my body) because when the hair grows it's thick. Thank you.