Bladder Neck Contracture or Stricture: This is a common complication following prostate surgery, including green light laser procedures. The timeframe of 4 weeks post-procedure is consistent with the development of a stricture, which can cause obstructive symptoms and hematuria.

Urinary Tract Infection (UTI): Although less common as a cause of hematuria in this context, UTIs can occur post-procedure and may present with hematuria, especially if the infection involves the upper urinary tract.
Prostate Bleeding: Residual bleeding from the prostate gland itself is possible, especially if the laser treatment did not fully coagulate all bleeding sites or if there was a recurrence of bleeding from the treated area.
Urethral Stricture: Similar to bladder neck contracture, a urethral stricture could develop post-procedure, leading to obstructive symptoms and potentially hematuria.

Bladder Cancer: Although less likely, it is crucial not to miss bladder cancer, especially in patients with a history of hematuria. The recent procedure does not rule out the possibility of an underlying malignancy.
Kidney Stone: A kidney stone could cause hematuria and might not be directly related to the recent laser procedure. The stone could have been present before the procedure or developed afterward.
Sepsis: Infection leading to sepsis is a life-threatening condition that could present with hematuria among other symptoms. Post-procedure infections can escalate quickly.

Arteriovenous Fistula (AVF): A rare but possible complication of the laser procedure, an AVF could lead to persistent or recurrent hematuria due to abnormal communication between arteries and veins.
Fistula Formation: A fistula between the urinary tract and another organ (e.g., rectourinary fistula) is a rare complication of prostate surgery that could present with hematuria, among other symptoms.