Yep, a trip to the audiologist for a fitting. You can also getting a hear test at the same time
. 15dB filters are designed for musicians who want to hear themselves. I got them for DJing and when at concerts and clubs, depending on how loud you play you might need 20’s. Years ago I started off with 15’s, after that I always use 20’s, I could even go higher. At a loud concert or club I can still hear the music well, but my ears often still ring afterwards. Prolonged exposure at anything above 85 dBSPL can potentially cause damage, which is a lot of situations, not just music related events. When in cities I sometimes wear them in the street.