We first see IG-88 here in the bounty hunter scene.

In the book "Tales of a Bounty Hunter" Boba Fett 'killed' IG-88 and he wound up here in the junk pile (next to the furnace). But for continuity, his color will have to be changed to match.

Another idea about this shoot is adding some flames from the furnace to make it more threatening.

Han lifting the Stormtroopers Helmet up and almost off

Pietts location Jump from here (front)

to here (the back)

First blaster shot

Leaves no burn mark but only a dot

Burn mark is now there

and laser shot hits the same spot again?

next laser shot,

no burn