A frog gets rub nose when he/she is not happy in their environment and tries to get out by "walking through the glass" as they have no real understanding of what glass is - they think they can seee through it so they can walk through it.
I would keep this froggie on plain white paper towel substrate, in a clean enclosure, change the water every day or more often if soiled and apply the Neosporin once/twice a day until healed. You should also be sure the temps and humidity are correct and place a background on three sides of the tank as well as provide plenty of adequate hides. Once he feels safe in his new home he will stop rubbing his nose on the glass and should be fine. Monitor him to be sure he is eating well and that the wound does not begin to get more inflamed or ooze any drainage. For further info about care on them, check out my site and feel free to ask any questions you may have. Hope this helps a bit.
www.froggie.info
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Happy Frogging!!! 

~Becki~