Yeah, extreme toxicity that will jump players straight to a permaban is more in the line of excessive hate speech or significant personal threats. But a more moderate amount of hate speech has been known to cause players to skip one tier of punishment. So if their next punishment would normally have been a 2-week ban, they would actually skip that and jump to a permanent ban instead.
With that in mind, here's how reform works as best we know. There's no set time period at this point, but over time if players are actively neutral or better in their games, they can climb back down the punishment tiers. That is, if you just had a 2-week ban and you're at least neutral for a while, you can drop down to where your next punishment would be another 2-week ban instead of a permanent ban. Even longer, and you drop down another tier, and then another, at which point your account would be back in good standing. Yes, Riot does have a permanent record of any and all punishments issued to your account, but that doesn't mean your punishment tier will permanently increase for life.
So in your case, it's been 2-3 months since your 2-week ban. If you've been at least neutral for long enough to climb down a tier, then awesome. However, that doesn't still make you immune to a permanent ban if your behavior in a relapse is severe enough to merit skipping a tier. On the other hand, if your behavior over those 2-3 months has been consistently slightly negative, though not enough to merit another punishment, you might not actually have managed to drop down that tier yet.
There's a lot of theoretical in this conversation, and that's fine if you don't want to get into details of your exact behavior. It just becomes up to you to honestly evaluate how bad you get in your relapses, and also whether or not you've truly been neutral or better since the 2-week ban.