App Didn't Update It Reinstalled Instead On IPhone

after updating my apps, I noticed one particular app didn't update, rather it appears to have installed a second icon for the same app instead, so there are now two identical icons, but one of them is grey and doesn't work, and when I hold down the icons to make them jiggle, it doesn't have an x for me to delete it. How do I get rid of this ugly waste of space?! Â

--I checked my app purchases, definitely only ever downloaded one version of this app.

--not an app that comes with the phone, so I should be able to delete it.

--there's no info below the frozen app (no progress bar, it doesn't say "waiting" or anything like that)

--I don't have a computer, so deleting through iTunes isn't an option.Â