@anjalima there are lots of tips to prevent radiation burn at this link https://connect.mayoclinic.org/discussion/radiation-burn-treatment/
I used fresh aloe vera and I had no problem. Just make sure you continue using it at least a week after the last treatment. I stopped a day after and the blisters appeared few days after the last round. The aloe vera gel at store (even 100% aloe vera) is not as good. Don’t worry so much. You’ll be fine.