Engagement ring feels off but I'm used to wearing rings on my ring finger

So just got engaged last night! I got proposed with a custom ring that I helped design with my local jeweler. My issue is that today I put it on again (since I don't wear my rings to bed) and a few mins later it started giving a dull ache in my finger (it's a continuum silver ring which is supposed to be hypoallergenic). The thing is before I got engaged, I've been wearing what I call my practice/leave me alone ring (great while working) and I got it cause I never wore rings before and I thought I should get used to it and I've worn that ring for about 2 years with no issues on my ring finger nearly every day. So should be fine since I'm just changing the ring I'm wearing? The custom ring was made with the same size in mind and I can twist it and get it off without much problem even though my finger is a bit swollen cause of the summer heat. I'm just wondering what I should do and why is it hurting if I'm just changing the ring even though that finger is used to rings.