This can happen due to temporary scalp dryness/irritation after head bath, especially with borewell (hard) water, even if there is no dandruff or visible rash. Since it settles within few minutes and she is otherwise normal, it does not sound serious.
Next Steps
You may try:
• Use lukewarm water instead of hot water
• Use mild shampoo only 1–2 times/week and rinse well
• Apply small amount of coconut oil/light moisturizer to scalp 30–60 min before bath
• Avoid vigorous rubbing while washing or towel drying
• If possible, try bathing once with filtered/soft water and observe difference
Health Tips
If itching becomes persistent, occurs even without bath, or if redness/flakes/hair fall develop, then scalp examination by pediatrician/dermatologist is advisable.