My guinea pig cant eat

Question
Hello,
We have 2 Guinea pigs about 5 yrs old. My daughter mentioned one was not eating very much, Usually she pigs out!! and she was fat. I should have looked sooner, I went to feed them and stayed and watched-sure enough she picked up the food and looked at it. I picker her up to check her from head to toe and she had lost some weight. I touched her everywhere to see if anything was hurting her. I payed alot of attention to her mouth and jaw and did not find anything wrong and looked inside her mouth. I also listened to her chest and it was clear. Her eyes were watery and nose a tiny bit wet. I knew if no nutrtion got into her she was not going to live. So I blended all her food and started to feed her a little at a time with an eyedropper! OH boy she is eating 3 x a day via eyedropper only with no problem ! I have a mixture of fresh carrots, tomato, red bell pepper and dry food. I did notice she can no longer sing like she used to. She also makes funny sounds as if she is trying to sing??? and she is drinking her water and is moving about the cage. What are good foods with vitamins I can give her. This has been 9 days long. Thank you for any help!

Answer
While I don't do guinea pigs as per my profile I know that if you tell me this pig is eating ground up food but not whole food she is having an issue with her teeth most likely.

Have the vet look in the back of her mouth and throat. Most rodent dental issues are with the molars way in the back, not the front teeth.

She might need to have one pulled or have them cut back there.