I'm no expert but I suggest you put some gauze/swab-like material on it (make sure it doesnt stick too much to your nipple though), like this,
I for one were given Cosmopor. It's an absorbent adhesive dressing, pretty good and could protect your nipples for now. If you think they are too wet, dont use the mousturiser for now and call the hospital and ask them to see you urgently and see what they have to say about it.
Also, 10 days of binding are not enough. I've had my surgery on 27th May (bilateral mastectomy, double incision) and I've got an appointment with my surgeon on the 10th of July and I will have to wear the binder until I meet her, and I'll see if she think it was enough. Keep wearing the binder 24/7, it helps a lot.
I suggest you check out jelonet, I've been using it and it's been great.
http://www.smith-nephew.com/uk/products/wound_management/product-search/jelonet/
How I usually do it is I take a shower, I put some moisturiser on the scars and nipples (It is very important to use a moisturiser without fragnance and it's recommended that you go to a pharmacy and ask for one specifically for surgical scars), let them be for an hour or so, apply jelonet on the nipple, then the cosmopor dressing. Been doing this for 10 days now and I'm healing super-fast.