some minor problems.

Hey. I have a gap where my bumper sags down a bit. Was wondering if anybody would know how to fix it.

Also, the knob for the A/C fan speed worked great when I got the car a couple days ago. But yesterday, it got really hard to turn. Like, the A/C still blows cold, its just really hard to turn the knob all of the sudden. anybody know what the problem could be, or how this knob even works?