I accidentally popped a pimple on my cheek very near to my nostril. i washed with soap and applied isopropyl with q-tip. is there any realistic chance of contracting a brain infection?

No: With a healthy immune system, acne should not cause any serious medical problems.

Pimple: No. A pimple should not cause any more than a topical infection at most.

Most of the time no: However, if this pimple is due herpes simplex, one can develop meningitis-like infection.

No: Unless you have some reason to be immunocompromised there is no reason to believe that "popping a pimple" will result in systemic infection. Your immune system is constantly challenged by bacteria from skin abrasions and your gut. Any release of bacteria from your pimple (which is a collection of white blood cells and bacteria) should be easily taken care of by your body's natural defenses.