Can putting cotton swabs in my ear infect my brain?

But..... ..It can puncture your eardrum which may cause serious hearing complications. In children, " never put anything smaller than your elbow in any opening of the body".
No. There really is no good reason for putting cotton swabs in your ear. Although you will get some earwax (cerumen) on the sides of the swab, the tip of the swab will push wax deeper into the ear canal. Frequent use of cotton swabs for ear cleaning often results in the opposite effect - an ear canal filled with cerumen and decreased hearing. I agree with the advice concerning elbows.
No. No. Unless there is a communication between your ear and brain... Which can be seen after skull trauma... But you would know that. In general, though, avoid putting anything "bigger than your elbow" in your ear.