I don't see it. Not the best pic though. You're prob seein a early onset of BR. Keep an eye on it. 

Take the whole cola off and maybe save some of it. Damp weather yes but it could be a worm, a moth larvae that started it. You can try different strains but the weather will always win. Check the rot for little tunnels that are made by a worm. Sometimes the worm is still in there munching but he's eating and shitting and moving forward. 

Thanks appreciate it. I cut it off got it hanging will give it a good look!