skycat is right mate if she has mastitis she needs treating at the vets ! mastitis is very easy to treat and responds well to most antibiotics if you know what your doing early treatment is the key, the plus side at four weeks the pups will eat and drink so they will be fine, feel the bitch around the nipple the signs your looking for are swelling red in colour hot to the touch, and when felt the bag feel lumpy above the nipple, if you try to squeeze the nipple and blood and shit comes out then its mastitis. hope this helps