Corruption not spawning in maps

I died in a corruption boss map while killing the main boss off the map but i still had revives left, after killing the boss it said "find the source off the radiating corruption" or something along the lines, i tried everything and explored the whole map and nothing was there, i decided to carry on mapping and now it says "travel too the corrupted nexus" but there are no more corruptions on my map or any red mist in the fog to indicate there are but it has acted like ive completed the corruption turning the remaining area into cleansed and fractured maps