Yeah, it looks like the air mix control lever cracked and fell down where it is in your picture. You have to buy the whole motor, unless you have the ability to scan and 3d print the lever. The part number is 79161-S6M-A41
Before you go getting a replacement, make sure the air control linkage moves smoothly. If it doesn't you'll need to try and repair the air mix door. If it can't be fixed, just get a replacement heater unit which will likely be used and include the air mix control motor.
Before you go getting a replacement, make sure the air control linkage moves smoothly. If it doesn't you'll need to try and repair the air mix door. If it can't be fixed, just get a replacement heater unit which will likely be used and include the air mix control motor.