What is the ruling on lying to conceal a physical illness, and is it permissible, out of necessity, to expose one's 'awrah to female doctors in the operating room?

Lying is forbidden in Islamic law and leads to wickedness and Hellfire. However, scholars have permitted it if it entails a predominant benefit without harming others, such as obtaining a right or averting harm. Euphemism (tawriyah) is better than lying. If you are compelled to undergo surgery, there is no sin upon you if there are women among the medical staff, as long as you are unable to prevent that.