Is this a fin nip injury or the start of fin rot?

[mtnmonster]

The white bulb on lower fin tip. It wasn't there yesterday  and all water parameters are back to normal and good. I did do a water change yesterday and I did notice one neon tetra attempt to chase the betta from food so I'm not sure if they've started fin nipping. He wouldn't hold still enough for a very clear picture but the spot looks a little fuzzy. Also what could cause a neon to become food aggressive?  Its not just the betta it chased away but the other smaller neon too. It has become a little bully this past week. This was the first time I've seen any aggression towards the betta.

[Colu]

If it's getting a fuzzy appearance to the tips of the fin it could have been nip and it's developed I fungal infection I would treat the fungus with ick x I would monitor the fins for now if the fins start to recede have redness to the edges of the fins then I would treat with kanaplex maracyn2 as most cases of fin rot are gram negative bacterial 

[mtnmonster]

I just got home while hooking up my light timer and putting a black piece of poster board on the back of the tank I noticed the spot is gone. I don't know. Should I still treat it? The betta is acting healthy, apparently he can see his reflection better and has been nonstop flaring at the black background. 

[Colu]

I would monitor for now if it gets worse then I would treat