Hi everyone I took my son for his 8 week check.everythkng was fine apart from the doctor commented on how he couldn’t lift his head from a lying down position on his tummy. However when sat up or out on my shoulder he is able to mostly hold the weight of his head upright. I’ve been doing tummy time with him and have a tummy time roll. However my boy seems more interested in chewing his sleeves, hands , or the roll. Is there anything I can do to strengthen these muscles. I’ve tried musical toys infront of him etc but he doesn’t seem interested . Thanks in advance