It depends on how much damage the other dog inflicted on yours. If it was just a little scuffle; make sure you have your vet give him a through examination to make sure nothing major is damaged.If...
i know this sounds insane but really what you need to do is take them on a walk together if possible. the walk should seem relaxing and this will help them relieve tension between the two of them...
Keep it on a leash around dogs you know it doesnt get on with, or on first metings with other dogs. Don't take them of it until you know how there relationship is going.