The character became invisible (The Elder Scrolls 5: Skyrim)

I started to take addition about vampires , and there's a quest which gives glanmor ( don't remember exactly his name )
And so , it is necessary to kill a vampire , I go into the cave I wrote equipped and appears around the character lightning , I think well OK can pass , then when you kill the vampire character actually becoming invisible .
That is , even not directly as a bug and as if it were a spell , and then sometimes I could see his aura .
A bunch of mods installed , but it's not their fault , have tried many things , don't know what to do (
pamagiti