I met a guy that I really liked. We dated and became BF/GF. I was in 3 months project abroad, everything was OK, he admitted his love and asked me to promise him never be apart even if I go back to my country. But one day I made a mistake he was angry and the culture differences started to show so. When I wanted to fix the problem I screwed it up more and more! Misunderstandings and communication problems occurred. So he used NC with me. I messaged him many times to clarify things, but no reply.

When I booked my ticket to go back to my country I went to see him and he was nice to me so we fixed a time to see each other in my last day there. So we couldn't talk or say anything. Then I gave him a present and he was happy and thankful and then when I started to cry he told me communication problem. And he hugged me I wanted to leave but he stopped me and kissed my head. I couldn't stop crying. So he was hugging me even though I pushed him away and then he asked me for a last kiss! After this he changed his picture for the first time in his kakao account, and wrote a sentence about being a worm which's turning right and left to become a butterfly proverb. It means like he's confused and complicated with his feelings as some of my friends translate for me.

Do you think he still have feelings for me?

I think if he still had feelings for you, he would have told you. The butterfly thing may mean that was turning right and left and was confused but now he is ready to be free.
If he did not say otherwise, he's done.

Doesn't matter until the real conflict is resolved, and that's in communications with each other. Love shouldn't need a translator.

Actually I already let him go when I booked my ticket to go back to my country I already knew that it is over... But I went to see him the last day just to say goodbye... And have a nice farewell.. but I didn't expect that I will cry and he will kiss me and hug me because he's a serious guy.
He don't smoke nor drink he's always busy with his work... COMMUNICATION was the main problem between us and his protective personality... So he was jealous because I went to party with my friends... That's the main problem and because of communication we couldn't fix the problem...

After this he just tried to keep me away... But I just want to make sure if he still have feelings for me I can learn his language and go back to him even after a year!

Because our relation seemed like heaven for both of us... But our differences turned it to hell !

This was a 3 month relationship. I would not take this so serious. If he really wanted to make it work with you, he would have found a way to communicate that.