Re: Strengthening Neck after injury
The weights you'd use to strengthen your neck would be very light...I think (and it was a while ago) that I worked up to about 2 lb (under 1 kg) for the heaviest resistance...
One "weight exercise" for your neck - lie on your back with your head/neck off the edge of the bed - move your neck and head through the full "forward/backward" or anterior/posterior movement range, trying to bend throughout the length of the neck, not just at the top of the neck. Too heavy? move farther onto the bed. Too light? do more repetitions for endurance, rather than adding weight.
Interesting that you feel you got "big". During the Phys-Ed degree (it was in the 70s so it may be considered politically incorrect these days) a woman in our "advanced" gymnastics course expressed a concern about getting bulky muscles - the professor said that most women can't grow big muscles like the males do, and added... (here's the P-I part) "Remember girls, under every curve, there's a muscle."