What should I put on my mosquito bite before it starts to itch?

Mosquito bite. Store aloe vera gel in refrigerator & apply to affected area. Rub basil leaf on bite. It repels mosquitoes & has anti-inflammatory effect. Consider applying calamine lotion or crushed ice or a cold pack. A 1 to 1 mix of water & baking soda is effective when applied to lesions. You can take oral medications like Benadryl (diphenhydramine) or Chlorpheniramine for itching.