Nodular acne tends to feel like a firm, solid bump deep under the skin, no whitehead, no soft squishy center, and it's usually tender or sore to touch. The bumps can be skin-colored or red, often bigger than a regular pimple, and they stick around for weeks instead of coming to a head and settling in a few days. Cystic acne, by comparison, feels softer because it's fluid-filled. If that sounds like what you're seeing, the honest answer is don't try to diagnose it from a mirror. A board-certified dermatologist can look at your skin in person, confirm what's going on, and put you on a real plan. Worth the appointment.