If in the last few days, you could have sworn you did actually headshot that guy in Valorant, it may be that you have in fact not gone crazy, as Riot devs have confirmed the game currently has a problem with hit registration.
Valorant v0.50 introduced many fundamental changes into the game, but it seems that it came with some unintended issues, and hit reg is currently one of the biggest.
Some players are reporting that clear shots are not being registered at all, others that it shows wrong parts of the body, while some say that hit reg is completely random.
"After the last patch, it seems like I'm shooting at them, hitting 4-5 bullets if not a headshot but only 1-2 bullets are registering, something is fucked up after the 0.50 patch," says Reddit user ChungMee. "I'm a 6K hours CS:GO player and a level 10 masters top 50 player on faceit, I can't kill on Valorant at all since the last patch, this is insane."
User IvoAlbino says: "Something is definitely not right with hitboxes since the last patch. Many times I've been aiming at the head, or even just actually seeing the enemies head, and it shows body shots."
Many are providing videos for their claims, where you can clearly see the issue. Shots are on target but not registered. Players are pointing out that they have stable internet and their ping is low, which indicates that the problem is on the server-side.
After a full week of complaints and discussions about the broken hit reg on Reddit, Riot is finally acknowledging that there's an issue and they are working to fix it.
Thanks to everyone who helped us find some new hit reg issues we introduced in the latest update. We're fixing them as we speak and they should be in the next update. Stay tuned!— Ziegler (@RiotZiegler) May 19, 2020
Riot developer, that goes by the name StealthyJesus on Reddit, explains the problem:
"We adjusted Deadzone accuracy with the 0.50 patch. Those deadzone changes exposed some movement accuracy desync between client and server. Your shots process correctly on the server, but the feedback you get on you local client can be at times incorrect, " he says. "This issue has been in the game code for a long time, but was previously quite subtle. It took the 0.50 deadzone changes to make it super obvious."
He confirmed that they are working on a fix, and that the improvements will be in the next patch or the one following.
If you're frustrated with the current state of hit reg, we advise you to wait for a few days and simply don't play the game until the patch arrives.