I wasn't sure how to answer this so I actually did a search on this same site and saw this:
Side Effects of Keppra - for the Consumer
All medicines may cause side effects, but many people have no, or minor, side effects. Check with your doctor if any of these most COMMON side effects persist or become bothersome when using Keppra:
Dizziness; drowsiness; irritability; sore throat; tiredness; weakness.
Seek medical attention right away if any of these SEVERE side effects occur when using Keppra:
Severe allergic reactions (rash; hives; itching; difficulty breathing; tightness in the chest; swelling of the mouth, face, lips, or tongue); abnormal thoughts; dark urine; decreased coordination; extreme dizziness, drowsiness, tiredness, or weakness; fever, chills, or persistent sore throat; hallucinations; memory loss; mouth sores; muscle or neck pain; new or worsening mental, mood, or behavior changes (eg, aggression, agitation, anger, anxiety, apathy, depression, hostility, irritability, panic attacks, restlessness); new or worsening seizures; pain, itching, or redness at the injection site; suicidal thoughts or attempts; unusual bruising or bleeding; vision changes; yellowing of the skin or eyes.
This is not a complete list of all side effects that may occur. If you have questions about side effects, contact your health care provider. Call your doctor for medical advice about side effects. To report side effects to the appropriate agency, please read the Guide to Reporting Problems to FDA.
I would at least contact the doctor to let make someone aware that your child is experiencing this side effect.