Can Silicon Gel For Scar Cause Hyperpigmentation On Skin?

Hi Dr. Andrew, i want to ask you something.... i heard that sillicon gel for scar is not a medicine but just a medical tool because of it s composition... so it s not classified in medicine or drugs nor supplement... is that true or not ? one more thing... i have an experience that i used a silicon gel for my scar but the reaction is hyperpigmentation in my skin... i have already asked my doctor about it but they said it happened (hyperpigmentation) because of the sensitivity of my skin... is that true ??? Thank you before... your sincerely Mrs Ani