I am a light sleeper and have been using ear plugs to bed for quite some time. 2 weeks ago, my boyfriend picked up some of Superdrugs own-brand earplugs, which are like a soft silicone putty. He wore a pair to a concert and gave me the remaining two pairs to use.
Despite the box saying they are suitable for sleeping in, after the third night of wearing them, I found that I couldn't remove one of them. It turns out that the squishy silicone softened so much with my body heat that it slipped down into my ear canal, and adhered to my ear drum. It is nigh on impossible to get rid of due to it