50 satoshi per byte is a very low fee, according to the current rates. Depending on the client you may be able to perform a childs pay for parent. I'm assuming you are using Bitcoin core though, considering you have posted it here in technical support. Really, the only option you have is either using a paid accelerator or attempting to use a free one. This is basically paying miners to focus on your transaction.
In future, look at this
website to find out what sort of fees you should be sending.