A huge pimple pops up under my chin just before my period... Ugh...

Of all things, I have an important appointment tomorrow, but a huge bump is poised to pop up on my chin. You all know that painful feeling when you touch it, right? I don't think a patch would help. In a situation like this, would it be fastest to just go to a dermatologist and get an anti-inflammatory injection? I'm too scared to even touch it because I'm afraid it will leave a scar. Please share some tips!