Generally speaking, sebaceous hyperplasia occurs in the older individuals or newborn baby. The picture isn't of the highest resolution so its a guessing game for those viewing it. When it comes to that specific disorder it should be promptly addressed if you fit into a category for a higher predisposition of skin related cancers. I know of a few off the top of my head that can be mislabeled as a sebaceous hyperplasia.

The hyperplasia term refers to the rapid cell division that occured to produce a abnormally enlarged sebaceous gland. Not trying to freak you out or anything. Just provding an opinion that covers the whole picture. You dermatologist would be the number one person to address these blemishes/abnormalities you have discovered.