Should I go to the doctor or will it heal on its own? Is there anything I can do to help?

Hello, my 10 month old daughter woke up this morning with several mouth ulcers (canker sores) on the inside of her lips and palate. I feel like she has bad breath too. She started daycare recently and had what looks like a cold (runny nose, congestion, cough...). These symptoms are still present and she has been losing her voice for 2 days. Her general condition is good, she does not have a fever and continues to eat well.