Betta bitta strangeness

(edit: woops, I should have mentioned that this issue resolved itself and that I am not looking for medical advice. My apologies for the initial confusion, I just wanted to know if anyone has seen something like this before)

A few days ago, I woke up to a strange look on my betta. His tail was all clumped together!:

It didn't look like it was melting, it didn't look infected...just--stuck together. My water perametres were great, my rasboras in the same tank were all doing well...I didn't want to fidget too much with the tank and stress everyone out. So--I just made sure the water remained healthy, that everyone was eating and behaving well...and waited to see how things progressed.The following two days, I noticed more clumps:

And I thought "oh no, it's getting worse! But upon closer inspection, it looked like the large clump had just come undone into smaller clumps. So I thought, "okay, well...maybe it IS a kind of fin melt happening..."

but, over the next few days, it gradually improved:

Today, he looks almost 100%:

I didn't change anything, I didn't medicate...I just waited--and watched closely. And it fixed itself.

Has anyone seen anything like this before? What would have caused that initial clumping to happen? It wasn't clamped, he was still fanning open his tail like normal--just that when he did, it strained against the ends that were stuck together. It also didn't really look or behave like melt, and it definitely wasn't rot... His behavior didn't change, he was still as active, attentive, curious, and hungry as ever. I'm stumped on what this was! Ah well, I'm just glad it doesn't appear to have been an actual health issue, as it's resolved itself very swiftly! Phew...