oh poor baby - I found when that happened with mine when they were little -a warm bath really helps - if you have a little nozzle maybe squirt some warm water on it gently too -
I'd def try to get in to see your vet if this goes on longer - he can give you something to soften it up some -
That's really hard to hear
Poor little guy - try vasaline in the meantime to take away some of the burning - he is probably really sore.
I hope he feels better soon !!