I had the same thing happen!
Good news: If it's the same as what I had, it will eventually calm down and disappear. There will be days where it swells a bit and itches like crazy (usually hot and humid days, or when you're sweating a lot), but it will go away.
Bad news: It took two years before it completely disappeared for me, but it didn't itch all the time in those two years, just on and off. Since it swelled so many times and also because I have no willpower and scratched it a little more than I should have, in places the red ink has turned kind of uneven. Not much though, and it's only noticeable if I point it out.
If I remember correctly though, I think red ink might always heal more slowly? It could be that it's perfectly normal and it's just taking a little longer than the rest, fingers crossed for that.