Just an idea where the amount of EXP gained for a skill would appear in the system tab of the chat, similar to how you would take damage and it would say "5.03 damage taken from (Enemy)"

An example would be if you're logging. If you chop down a tree, it could say "Gained 0.02 Logging Experience" or "Gained 2 logging experience", something to that degree, but will be displayed in the system tab.