Forgot to Remove the Sticker During Immersion of Utensils

I immersed a plate and later found a sticker attached to the bottom. Do I need to immerse it again, and if so, with a blessing?

If the sticker does not bother you, it is likely that people do not insist on it, and there is no need to immerse again. If you are particular about it, immerse without a blessing.

Talmud, Eruvin, page 4, side 2: "According to the Torah, if most of it is covered and one is particular about it, it is a barrier, and if not particular, it is not a barrier. They decreed that if most of it is covered and not particular, it is a barrier because of most that is particular, and if a minority is particular, it is a barrier because of most that is particular. - Why not also decree that if a minority is covered and not particular, it is a barrier because of a minority that is particular, or because of most that is not particular! This itself is a decree, and shall we decree a decree on a decree?" Also in the tractates Bocha and Nida.

And this means that in the immersion of a person and utensils, most covered, even if not particular, or a minority that is particular, is a barrier. But a minority that is not particular is not a barrier, and it is customary to be stringent in this, as Rema wrote at the beginning of chapter 198.

Regarding being particular, Rambam implies that it depends on the person immersing, but in Tur, chapter 198 and Shaarei Refua, it implies that it depends on the opinion of the world. And so ruled the Shulchan Aruch, Yoreh De'ah, chapter 202, section 2: "Anything that is usually considered particular is a barrier; if not, it is not a barrier unless it covers most." This implies that it depends on custom, and therefore, if particular, one should consider Rambam's opinion, as Aruch HaShulchan wrote in chapter 198 and chapter 202, and thus immerse without a blessing.