Traumatized Cat need help..?

I've had my cat for like 6+ months. He was a little timid at first, but changed almost immediately. he never was one to scratch, or bite. he was always playing or sleeping and liked contact.Today he was at my moms(usually at dads), and she had with dogs who he plays with, and i let the dogs out because he doesnt like being picked up when they can see him.lol. well i picked him up, he wasnt to happy but nothing serious, went to the couch and then he started to claw, (try to escape), and i just grabbed his scruff(very lightly). Usually settles him right down. well then he out of nowhere went nuts and scratched me and then bit me, hissed and ran. I was leaking pretty bad, he got me good. I went over to pet him to tell him its okay calm down, and he was scared. So i went and showered and washed my wounds, and figured it was time to try to tell him again its ok. He was absolutely traumatized and was very scared of me, and went to a corner and just stayed there. He was scared to move, and watched everything i did. I finally got to him and just sat and petted him for like 15 minutes, but we was terrified. And i rarely hit my cat, and when i do he laughes in my face. I usually just flick his ear or something tiny. He finally left, went upstairs in a crazy run out of pure fear, and then slept on the bed. I went in and he woke up, he seemed fine for a split second, but he was still terrified. He then let me pet him again, but was very fearful. Pupils are still dialated... after a few attempts of me going and petting him, while i was watching tv he came down the stairs and ate. he then went into his room(my brothers) and layed there. I went in and he was still scared. I kept going in and sitting with him and petting and talking to him, and he seemed to be getting somewhat better. This is like 10 hours after the incident and he was still scared. I went in later, and even though he is still traumatized and very aware of every movement, he started to purr this time. I then tried to pick him up, not towards my face, just from ground onto bed. he was alright but once he hit the bed he went wild again. He just ran off and hid. I went over to his cowering, and after a bit he started to purr. I let him be again. I went in later with my mom, and he was more reluctant and scared, but eventually purred. I thought maybe he broke something like a rib, but he was starting to roll on him back for belly rubs, and I felt his ribs and he did nothing. I may have gripped him hard n his side or something when he started to scratch, just out of reflex, but he seems not injured. I would like to know what you think it could be, if youve ever experienced this, and what i should do. Im seriously considering a vet visit. Any questions and ill answer. i just want my cat back. If you dont have any info, i could really use some spirit lifting. He is a great friend and i just want my friend back. He was bought from the shelter, and he definatley had been hurt before, but his attitude was like nothing ever happened.