Thanks for your query.
Outcome after burns depends on the severity. In mild (superficial) and moderate (partial thickness) burn skin usually heals without scarring. But in severe (full thickness) burns all layers of skin are damaged resulting in permanent scars. I am assuming that your wife had sustained severe burns which is treated by skin grafting.
Apart from scar hyper pigmentation is another complication of burns. If this what you consulted the Dermatologist then the medications you mentioned do help to improve the appearance.
Whether any other medications are indicated in your wife's case depends on the proper assessment.
Next Steps
You should continue these creams at least for 2-3 months to assess the response of treatment.
Health Tips
You can consult another skin specialist for second opinion if you are not completely satisfied with the first consultation.