Totally understand how you feel! My darling baby has the gorgeous golden ringlets I have dreamed of ever since finding out that DH has naturally curly hair (he keeps it cropped, #2 all over lol). Well.... that was until the day my wonderful DD1 decided to play hairdresser and hack her poor baby sister's curls - which were past her shoulders - right to the scalp.
However, I'm pleased to report that DD2's curls are growing back just as curly as before, and feels thicker and more easy to manage (less prone to tangling, smoother to brush etc) after her 'haircut' I'm sure your little man's lovely hair will grow back just fine, and hopefully he won't look like an escaped lobotomy patient while you wait for it to grow out hahah Good luck!