Will keeping false eye lashes on overnight create discomfort while sleeping?

It shouldn't cause any major discomfort, however if you're using a strip lash then it can be easily peeled off and re used the next day anyway. I personally would always remove all make up before sleeping. Individual lashes are different in that you can leave them on for up to a week, and still wash your face daily, just being careful around the eyes.

I agree with SolarCentreBeauty, individual lashes are designed for longer term wear. If you're wearing strip lashes. Reward youself at night with a superficial cleansing regime. Fresh skin and bright eyes in the morning ready and prepeared for makeup. Please try to avoid sleeping in strip lashes for the sake of it - you might end up with blockages around the eyelid which can lead to an infection. So please take care.
Dawn FD
NailTacTix