This is totally allowed. Not only borrowing, but flat out taking/moving money from one category to another. A flat $200/month is not a really good budget for shopping like clothes - some months you may be under $100, but once in a while you may find a good deal or something that fits super well and you want to spend 5 times as much. As long as you're able to cover it from another category without dipping into debt, go for it.

There is a popular budgeting app called "YNAB", and they have a set of 4 guiding principles. This adjustment of categories is number 3 of the 4 rules: https://www.youneedabudget.com/the-four-rules/#rule-three