4mos old baby doesn't like looking at people's faces

Has any parent here experienced that their child doesn't make eye contact to people even to you? before, when i talk to him, he smiles and keeps his eyes on me. but when he turned 4mos, he doesn't look at me even when i talk/sing and put my face close to his. people around us are starting to ask us why he doesnt look at faces. when face him he looks away to avoid eye to eye. im so worried. i read some articles of asd. some, they experienced it but resolves months later. we've informed his pedia already, and he's for evaluation on his 6th month. i wanna know if any of you have experienced it and what happened then. thanks all