Bedieved if circumcised at night:[1]

In the event that one transgressed and performed the circumcision at night then [one does not fulfill his obligation[2] and thus] he must repeat and perform Hatafas Dam Bris during daytime. [Some Poskim[3]  rule that in truth the Hatafas Dam Bris is a mere stringency, and hence the Hatafas Dam Bris may not be done on Shabbos and a blessing may not be recited over it. However, other Poskim[4] rule that the Hatafas Dam Bris is required from the letter of the law, and hence may be done even on Shabbos and is to be performed with a blessing.[5] Practically, one is to suspect for both opinions, and hence although the Hatafas Dam Bris must be performed, nonetheless it is not to be done on Shabbos, and is not to be performed with a blessing.[6] According to all opinions, if one merely performed the Peria during nighttime, then Hatafas Dam Bris is not required.[7]]

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[1] Rama Y.D. 262:1; Pesakim Uteshuvos 262:8 footnotes 49-50; See Encyclopedia Talmudit Vol. 46 Erech Mila p. 488-4492

Other opinions: Some Poskim rule that Hatafas Dam Bris is never required as it does not accomplish anything, as what was done was done. [Shaagas Aryeh 52; See Pesakim Uteshuvos 262:8 footnotes 53]

[2] Shach 262:2; Taz 262:2 even according to Rama ibid; Shaagas Aryeh 52; See Pesakim Uteshuvos 262:8 footnotes 51

[3] Taz 262:2; Bach 262; See Pesakim Uteshuvos 262:8 footnotes 51-52

[4] Shach 262:2; See Pesakim Uteshuvos 262:8 footnotes 52

[5] See Taz ibid and Shach ibid; Beir Heiytiv 262:1

[6] Bach 262; Chochmas Adam 149:2; Aruch Hashulchan 262:5; Pesakim Uteshuvos 262:8 footnotes 54

[7] Maharam Shick Y.D. 240