>Is this cheating the system?

Not really. A budget just exists to ensure your overall expenses remain below a certain level. Doesn't matter if you have discrete line items for make up, clothing, and haircuts or if you combine all of that into a single "makes me look good" budget.

If you overspend in a certain area, it may make sense to increase the granularity of the budget (i.e. not allowing yourself to spend more than $X amount on Video games, or booze, or whatever you spend too much on)