More likely a ligament or tendon.
Soak it in a bucket of cold water and keep adding ice cubes.
Then stand on your foot in different positions while it's in the bucket.
When you can tolerate the cold and have no more pain, then you can run on it.
|been there before|
Likely a tendon or ligament
I could feel a 'squeaky' feeling when I flexed my toes upwards.
It went away after some good icing and with continued training with no time off. Don't run on uneven surfaces for a while though. That is what aggravated mine.