Hi My 6 Week Old Baby Fell Off The Bed

Hi my 6 week old baby fell off the bed while I was sleeping. I was awoken by him fussing not crying. He didn't fall on the ground however. His bassinet was right next to the bed and he somehow managed to fall into the storage area under the bassinet. He was face first and I'm really not sure how long he was there but he seems fine three days after. However now my sons soft spot is feeling rather firm when it didn't just yesterday. Yesterday it felt rather soft and kind of sunken in. I haven't seen a doctor because mine are closed what's wrong with him is he okay. Should I take him to the hospital?