As per my suggestion visit a dentist and get her prescribed some antibiotic n painkiller so that her pain shld be relived... Kindly avoid  giving her bottle feed at night while sleeping  ..get her teeth brushed at night ...or proper rinsing should be done. As per the treatment part. U have to do quiet a lot counciling for your kid before going in for treatment because it not easy for such a small kid to go under this procedure until n unless she is having repeatative problem ,as u only said she doesn't allow u to brush her teeth so treatment part is far more not possible right away ...just make her do regular brushing by teaching her or in a play full manner .. do visit a dentist so that  she get confidence prior getting any treatment ..because once if she get scared she won't sit  on the chair that easily so thats my advice .

Most probably your daughter having nursing bottle caries. You should visit some pediatric dentist. Stop feeding with bottle.

Visit a dentist, this is a vague history. Relieve her pain first and then diagnose at a dental clinic. She would probably need a root canal treatment.