Allright. Thanks He is quaranteened and I will keep an eye on him.

Of course I couldn't find the thread here where someone posted a pic of his Green Treefrog, who has similar patches (although his patches had also become swollen), but I found a thread here that states it's most likely scar tissue: Field Herp Forum • View topic - Fungus on toad in DE

He has the exact same spot. So fingers crossed and all - will keep an eye on him