Why do some pimples refill after popping them?

I clean the area, making sure everything is removed I stop after clear fluid or blood, and just in case, I apply a hydrocolloid. However, the area seems to shut very quickly, and I have to repeat the procedure because when I wake up, the region is still red and bloated with pus.

Pimples can refill because not all the pus or bacteria gets removed when you pop them. Sometimes, popping can push stuff deeper, causing more inflammation. It’s usually better to let them heal on their own or use treatments to manage them.

Every real pimple (not just clogged blackheads) has what I consider a core. If you don’t remove the core, the pimple will return. I only pop a pimple when I’m confident I can get the core out; otherwise, it damages the skin and takes much longer to heal. However, removing the core helps it heal faster than leaving it alone.