Bit the inside of my cheek a couple times and now have a small bump that is dark red/black; is this just dried blood? feels like a pimple

Probably so: It is probably dried blood or a blocked minor salivary gland with blood inside it. If it does not resolve completely in 2-3 weeks-see you local ENT or dentist to take a look.

Most likely: It's dried blood or a blood blister from repeated bites. It happens all the time with sores on our tongues & cheeks. We bite them once then keep biting them since they protrude slightly. Slow down when eating, be extra careful & it should heal in 2-3 days. If you keep biting it or it stays a problem see your dentist. They may be able to grind a small amount of 1-2 teeth to help you stop biting.