biting/sucking wrist and arm :-(

[mamacita]

My 16 month old boy has been sucking and biting into his wrist for 3/4 months now. After observing him I've worked out that he does it for comfort (going to sleep or when tired) and when he's frustrated(strapped in car seat)he also has a comfort blanket which he holds in his hand whilst sucking/biting on his arm/wrist.
I've tried to gently encourage him not to do it by taking his wrist away and telling him - "please don't bite your wrist you'll hurt it" etc. I've also offered teething rings, muslin cloth, carrots etc to bite on but he just rejects them.
He does it alot each day, the skin on his wrist is red and broken but he doesn't stop - I've wrapped a bandage round it to help it heal and he doesn't suck the bandage - but then he sucks further up the arm or the other arm.
It really upsets me to see him like this - he is otherwise such a happy, smiley and active child. He was breastfed and has never had a dummy.
has anyone been through this? Should I just let him grow out of it? or can you offer any advice to stop him?

dd just grew out of it but i found it distressing. It didn't go on for very long, i remember but it is a bit hazy - sorry i can't be more help

My 9month old boy has been doing the same for about a month (sucking his arm constantly almost as though giving a love bite) now & I am begining to develop a real issue about it as he does it even when he is surrounded by toys & my stimulation. I figure, yes, it might be comforting but doing it all the time, is it really necessary? mamacita has your little one stopped doing it yet & did you find a way to stop it. People point it out to me as though I've not noticed or think its really funny. My patience is wearing thin & im desperate for advice!