Default sd card not mounted on lg l3 e400

I have a lg optimus l3 e400.
I am new to rooting and stuff.. Recently I rooted my phone and it worked well. Then I installed this sdmerge mod.
And installed this version of cyanognmod :
I have a 8GB external memory card. It was working fine then. But later I connected the sd card to my laptop using card reader and formatted it(FAT32). From then on the phone is not mounting the sd card! It only says that sd card is not mounted. The sd card couldnt be mounted even in cwm recovery. The version of cwm that i had was some v6.0.0. something. I later flashed v5.8.4.5 cwm recovery and even that is not mounting the sd card! I tried formatting the sd card even with NTFS or ext2 but nothing helps. The card works fine on other phones. And my phone detects other sd cards properly.
Also I even did data wipe, cache wipe, dalvik cache wipe and reinstalled the whole os. Nothing is helping out.
Any kind of help is appreciated.