I'm diagnosed with subdural hematoma, and needs surgery immediately.but could this surgery has any side effects later on or could it threaten my life?

This surgery is safe: Subdural hematoma may be minor, requiring no treatment, or large and life-threatening. Generally surgery is recommended if the hematoma is causing symptoms or is large on ct or mri. The primary risks of surgery are infection and rebleeding, possibly requiring reoperation. The risk of brain injury or long-term side effects is low.