Caleoderm will not help it only relieves the itching. I would like to know if the sunburn is since few days or is it many days old.
Treatment varies accordingly it also depends if the hyperpigmentation is superficial or deep.
Try using ban a tan cream once at night and use a good sunscreen like Rivela gel sunscreen in the morning every 4houts and it should get better if it is superficial.
Hope this helps
Dr Batul patel