What should I do if I have a fever after getting the measles vaccine?

Patient's question:

Symptoms: High fever
Onset time: This morning
Laboratory test results: None
Previous treatment and effectiveness: The child is 12 years old. In the morning, they had a slight fever and received the measles vaccine at school under anesthesia. Now they have developed high fever and don't know what to do.

Doctor's answer:

12-24 hours reappear, 48-72 hours pain subsides, tenderness: 12-24 hours reappear, 48 hours-7 days subsides. Enlarged lymph nodes, lymphadenitis: 24 hours to 1-2 weeks or longer. Systemic reactions: Fever: 8-24 hours, 24-48-72 hours subsides, Toxic symptoms: Dizziness, headache, fatigue, general malaise, 1-2 days subsides, Gastrointestinal symptoms: Nausea, dry vomiting, abdominal pain, nausea and vomiting. The local anesthetized area has redness, swelling, heat, and pain, except for fever, headache, and general malaise, infants and young children reappear restlessness and crying.