Hi I would suggest you to visit a dentist nearby and get it checked. Sometimes feeding milk leads to cavities in front tooth which can lead to infection. In order to avoid any infection and rule out the exact reason of the swelling I would always suggest a check up because without having a look at the baby it is difficult to give a judgement whether any treatment is required or not. In case of pain you can continue with combiflam but better show her to your nearby dentist.

Hi Gum discoloration (dark pigmentation) is quite normal. Gum pain might be due to any tooth brush injury  . Give her a soft brush .Give her crocin or paracetamol suspension for pain.Visit nearby dentist .