My 22 months wakes up at night to scratch herself after playing on the lawn. Any OTC medication we can try? Best Antihistamine for lawn?

Nocturnal itching. I am concerned about the possibility of insect bites or infestation(?from chiggers)from playing in the lawn. Observe for any evidence. Your pediatrician can recommend the proper dose of benadryl which is antihistamine and antitpruritic as well as being a mild sedative.