It was RUNNY even???
And HURT a lot, and then started to be runny?
But now no longer hurts?
Well, either whatever kind of matter had built up BEHIND your eardrums managed to pierce them in one place (pressure relief - no more pain), and came out (runny ear), or you had an infection of the acoustic meatus, which also gives you runny ears, but nothing INSIDE was infected.
A doctor must find out WHAT part of your ear was infected. And what CAUSED the infection. Viral infections heal themselves out all by themselves, bacterial infections do require antibiotic treatment.
But as to your question whether it gets worse again ... not THIS infection. But if you leave it all untreated, the next might get worse...
Says who suffers from never-ending infections of the acoustic meatus...