I was in forest yesterday and checked myself, but now have cyst-looking pimple on neck. could it be a tick bite? i get cysts but usually hairline.

It could be: Almost all insects bite leave a small cysts like pimple but often ticks leave the head in the lesion. You can be tested but only by reputable labs.

Likely not a tick: Ticks stay on for many hours to days after biting, usually. They attach and feed. If a tick was not found within a day, then something else bit you, if it itches or hurts. If not it may be a pimple/cyst. Wear insect repellant always, so you don't have to worry about insect/tick borne diseases going forward. Keep the area clean and watch it. If it gets worse, get seen.