Pupil got bigger than other n now normal

I get alot of white stringy mucus in my eyes . So I usually look into my eyes using phone flashlight , last night I was doing the same , till then my pupils were of the same size but after 2-3 mins my right eye kinda started irritating me so I saw in the mirror and to my astonishment my right eye pupil was bigger than the left one . It wasn't constricting ( i.e it wasn't getting smaller when I was going in light, it was getting just a bit smaller not as usual) . I freaked out .. it was like that for 10-15 mins and then I closed my eyes and it got normal after 10 mins . Now my pupils are of the same size and I also used eye-cool drops yesterday . What could be the possible reason for this? Is it something serious? (And I even have a bad habit of touching my eyes again and again )