Lakers Star Nick Young -- ROLLIN WITH IGGY ... After Thumb Surgery

Iggy Azalea was standing by her man Monday ... even when he couldn't ... escorting Lakers star Nick Young out of a medical building following surgery on his thumb.

Besides his GF, Nick's parents were also there as he was wheeled into a waiting ride in L.A. -- after undergoing surgery to repair the torn radial collateral ligament in his right thumb.

Despite the fact he'll be out for 8 weeks, we're told Young was still smiling on his way out of the surgical center ... possibly because he'll still be raking in paychecks from his new 4-year $21 million contract.

That'll make ya feel better.