Hi Lille,
It’s possible she is constipated. KMR/PetAg concentrates will give kits constipation. Here in TDKland, we recommend Goats’ milk for kittens. Cats are lactose intolerant and can’t digest cows milk. Goats’ milk is full of nutrients, probiotics and gentler on their tummies. This can also regulate their poop. If you are using the Goats’ milk concentrate, mix it with pedialyte. Pedialyte gives an extra the extra boost. Keep in mind if they seem lethargic put a dab of Karo syrup or honey in their mouth. Sometimes this is all they need to give them the added energy boost to get them eating. A smidgen of mineral oil in their formula can usually help them poop. Here are some links with good information on caring for your wee kits.
http://messybeast.com/handrear.htm
I can’t think of what the bump is so I recommend calling a vet. If you need a low cost vet here’s a list of them Nationwide:
http://www.humanesociety.org/animals/resources/tips/trouble_affording_pet.html?credit=web_id91754962#Assistance_by_state
Good Luck and keep in touch
PG