Is this cystic bump, a boil or spider bite?

Has to been seen: Without looking at the site, most of us are unable to completely diagnose but only speculate. If it is painful it could be a boil, infected cyst or even a recluse bite (depending of the timing of the pain and bite if known for sure). If not painful, it could be a cyst, lipoma, insect bite with induration or an evolving boil. Hard to say without visual examination.