Beneath rock bottom is a trap door.

What most people call ‘rock bottom’ is just their personal bottom, where they, personally stopped digging themselves deeper and instead turned around.

But, yeah. Until you’re dead, it can always get worse. Always.

Rock bottom is no objective state but a psychological one where you literally can’t care anymore and feel indifferent towards dying or consequences.

Somewhat ironically, i needed to get to that state to discover that once i had given up, nothing could hurt me anymore and i could do whatever I felt like without worrying about societies weird rulings and restrictions.

Never ended up doing anything that was really outlandish but experiencing that knowledge of absolute freedom and freewill (anarchy) kept me going long enough for it to become an escape vector to climb to a condition where i could care once again.

Physically, only a finite amount of information fits in a given volume (e.g. your skull) before it collapses into a black hole. Among all possible configurations of information within that volume, some set of configurations is going to be the worst. So it can’t always get worse.

Though if you’re talking about your experience, then yes things can always get worse by lifting the restriction that it has to be “your experience”. Whatever criteria you use to define “your experience”, your worst possible experience will bend the boundaries of those criteria to find near-inhuman levels of suffering.