I don’t think so. At least it doesn’t seem to cause any problems in my family, where everyone is called by two or three different names. My parents always called me “Mutt,” for reasons lost in antiquity. My maiden name was McDonald, so most of my college friends call me “Bettye Mac” or simply “Mac” (as it was fashionable to use last names only when I was in college). My oldest granddaughter named me “Monie” (sort of a variant of Mommy) when she was just learning to talk, and now almost everyone in the family calls me Monie. My husband’s name is Fred, and his parents always called him “Son John.” I call him “Champ.” He calls me “Em,” and I have sort of forgotten why. I could keep going, but I won’t.
Whatever you call your son, say it lovingly. Sometimes use both names together so he will realize that both names are valid. When he learns to print or write, make certain he learns to print both names.
And kudos to you for continuing to mother your son in spite of your earlier health crisis. I suspect whatever you call your son, he is going to know that you love him.
Our parenting advice is given as suggestions only. We recommend you also consult your healthcare provider, and urge you to contact them immediately if your question is urgent or about a medical condition.