Can missing birth control cause redish-brown discharge for multiple days? also what should i do if i miss a birth control pill?

YES: The hormonal cycle can be disturbed and cause some breakthrough spotting if you miss pills. If you miss one pill, then take the pill when you remember it, this will still provide protection in the cycle. If you miss more than two pills in a single cycle. The pills are not effective anymore that cycle and you must use back up birth control to prevent pregnancy.