^The last two guys must have read my post. But it's the most logical explanation in any case.

maybe they forgot it?

Slica

Maybe the Dragon Amulet has abilities that he wasn't aware of and he managed to heal the scar

Maybe in MK3, Subby was painting his wall with red paint, and Cyrax burst in looking for him, and in a panic, he whirled his arms around and got paint on his face. Then in MK4, the same thing happened when Scorpion came bursting through his wall, as he was painting it again, and Subby panicked and got paint on his face again? Then in MKDA, Subby was painting his new Lin Kuei temple, and the phone rang, and he was so startled by it that he once again slipped with the brush and painted a mark over his eye...though this time it was blue? I'd always imagined Sub-Zero as being a bit of a klutz when he's not fighting.

the good thing about mk is that every game in the series can have its own sequal, and its own prequal, a prequal to mk1, think of the possabilities.

have it like when goro and shangshung first took the tournament.

the possabilities are endless, and there is so much material created for it, every character could get its own spinoff, bad or good.

ha.