Is it healthy to sweat at nights ? sometimes when i sleep i wake up sweating a lot or sometimes i wake up just sweating a little bit

Depends: This depends on the reason for sweating. It may be too hot, you may be using too many blankets, or may actually be running fevers at night. Suggest you take your temperature, but not when you are sweating but before the sweating usually starts. Sweating is one of the ways the body loses fever and if you take your temp while sweating it may already be back to normal. If fever see a doctor asap.