what part is this? How can I fix? Thanks!

 

Find the part number by typing your vin into dreamshop.acura.com.

Check youtube for the crash repair videos of someone repairing this model (or the identical 2018 or 2020). They usually remove and replace door trim before painting and often record this step. Or the "official" instructions are available by buying a 1-day subscription to techinfo.honda.com.

 

Depending on which side, it looks like either #11 or #21?
Front Door Locks - Outer Handle - 2015 Acura MDX 5 Door BASE KA 6AT (acurapartswarehouse.com)

 

Can the outer door handle be replaced without taking off the inside door panel?

 

No