This is likely a swollen lymph node. The body is full of these lymph nodes (also incorrectly called "glands" by many people). These nodes are resposible for fighting infection. No surprisingly, the become noticable during a cold or flu or other type of illness. Normally they are about 1/4 inch, round and soft. They can swell temporarily to 1/2 inch or more.
Don't get too excited about it. Just keep track of it. If it stays the same size or gets smaller, you're fine. If it gets bigger over the next few weeks, then have a doctor look at it. Finally -- DO NOT RUB IT -- this will only inflame it an make it bigger!
It could still be lymph nodes. It could also be a cyst as you mentioned, but these usually go away in a few days. Finally it could be acne or an abscess (deep skin infection with pus). These are usually painful and red.
In any case, if you are really concerned, then stop by an urgent care center in the next 1-2 days and have it looked at. It's very unlikely to be anything very serious at your age and given the location (cheek).
Finally, if you are a smoker, please stop. Whatever the lump is, the smoke will make it worse.