heat sink screw

Hi everyone, I own an ASUS TUF FX505GE gaming laptop. Recently I opened my laptop panel to re-paste the thermal paste and found that my screws were stripped. I don't know the screw size. please help me ASAP. ( I don't know if its m2 x 3 mm size or m2.5 x 3mm size). Also, how do I screw them back...