My Cockatiel is very aggressive and scared.

[llvhxll]

I got my cockatiel 2 months ago from a pet shop, once i got him i realized he was really scared and i knew that was normal at first since it was a new environment and new people but it has been two months and he is still scared of me and anyone else who come even remotely close to him, although i have never tried to handle him roughly for screamed at him, i always speak softly with him and sit with him as much as i can. I tried to put my finger in the cage once to let him nibble on it to get used to me but he reacted aggressively and bit me really hard which made me bleed and yelp out and scare him more, which i regret a lot now.
Can someone please tell me what i can do with him?

 

[DiscotheCockatiel]

I would get some millet and put your hand in the cage with the millet in it and your finger out. Don’t push him or force him to step onto you just be there and let him come to you. He is scared and treat him as if he were a wild bird (he pretty much is) this is what has worked for me with my tiels.