My toddler ran into the corner of a wall hit his forehead. bump felt like it was filled with something. couple days later his entire forehead is squis?

Squishy feeling: Your child had some head trauma a few days ago. The most serious prognostic sign is "loss of consciousness" which you didn't mention so that's great. Nevertheless the tissues nearby swelled and that swelling will regress in time. As it goes down you may feel a little bump on the skull right where he hit himself (new bone formation). That too will resolve but probably in 9 months time.

This may just be: the underlying fluid/blood from the initial bruise, just spreading out under the superficial tissue, but at his age, I wouldn't take a chance. You should take him to his pediatrician to be examined.