So after receiving some asphyxiation damage and waiting a few hours for it to heal completely, I noticed that the -5 intelligence penalty was still in effect even though the wound itself had already healed.
My intelligence due to the "wound" that had already healed.

Picture of my health screen.

Only after logging out my character (and having to wait for it to completely log out, otherwise the penalty would not go away), did my intelligence go back to normal.

I assume this could also happen with other wound penalty types. This is nothing too gamebreaking, but definitely something that could cause some confusion.