In order to exerience Terraria events without waiting until Christmas I changed my system time from the current time (September) to December.

Skype messages that I received during this time were logged as if they were receieved in December, I thought that maybe this would be fixed when I changed back to September or at least new messages would go beneath the ones in December. However this is not the case and it is extremely annoying having to scroll down all the time to read messages as I type with a friend.

How can I remove or fix the date stamp of these messages in December?