If your lips are falling off from the amount of soothing shushing you've been doing then Baby Shush is THE skill for you. Baby Shush uses a thoroughly tested technique designed to break a baby's cry spell and engage their natural calming reflex.
The rhythmic shush reminds baby of being inside mom, where they were inundated 24 hours a day with loud sounds of blood flow and other in utero noises (up to 95 dBs, or the sound of a very loud vacuum cleaner). What may sound harsh at first is actually very calming to a baby.
It will play on loop so you don't have to worry about baby being suddenly woken up.