My 2 year old daughter has a lump under her chin on the left side and rush on her chick. her brother had mumps 2 weeks ago and spent 4 day's in hospi?

Likely lymph node: The lymph nodes in the body strain body serum of germs or debris before allowing it to return to the circulation. This lump and its location likely reflect a reaction to the face rash & not mumps. Nodes enlarge while doing work and shrink back to small size over a 2-3 week cycle.

Mgt: I would suggest monitoring for fever, rash and other signs of illness. Follow up with your PCP and review all immunizations.