You know, I've long likened trans people to artists.
We see our bodies like a painter sees their most recent painting. We pick it apart, we criticize it, we put it down, we insist to everyone around us that there's something wrong with it, even when other people see it and think it's perfectly fine, and in many cases is absolutely gorgeous.
Every cis male I've met, has had their own version of that same problem. They feel it too, for sure. My brother is masculine, tall, and very handsome, and he constantly remarks about he dislikes being so short (5'9) or his hands are too small, or his head is too long, or his legs are too curvy.
The truth is that we are our own worst critics, and it's hard to ask someone you know for an opinion because automatically you believe deep down that they will tell you what you want to hear, even if what they're saying to you, really is the truth but you can't see it.
Now as for a magical head size increasing pill...There's of course no such thing as pills which are magic.
Everyone knows magic medicine is in the form of powders and elixirs!
But aside from that, many men I've met in this incredible community have mentioned that their feet, hands, head, necks, and wrists have all grown larger while on T. The bones can't suddenly change shape, but the muscles, fat, ligaments, etc. Can indeed thicken enough to make you go up a shoe size, or a hat size.
And take it from the man who's made costumes for a living, I've gotten some of my smallest head measurements from men who looked perfectly normal and proportional, even if the circumference and length of their skull was smaller than the average female customer.
I myself range on the small side, and all that does is make my shoulders look bigger!
Now, to address the voice issue.
I have to respectfully disagree on it as a large scale generalization, because the majority of trans men I have met have clearly male voices, even some who haven't had a drop of T.
Yes, some FTM guys DO have slightly more feminine sounding voices, or speech mannerisms. But many of these guys on Youtube are either in the process of beginning their journey into transitioning (Which major vocal changes can happen as quickly as months, or as slow as years depending on your genetics, where you start, and if you do any vocal therapy to assist it.) or are still in a masculine vocal range, but are being listened to by someone who's attuned to picking out flaws in other people's voices, because they do it to themselves, and to discern their own likelihood of being able to sound male based on other people's results. (Which is actually quite inaccurate, mind you.)
All of these things...We pick them out much more harshly than the cis people we're living side by side with, because we think we need to.
But the truth is, we don't. We come in as many shapes and sizes, sounds and looks as cis people do.
Dysphoria hurts, but try not to let yourself be discouraged by self judgement. Transitioning may not be for everyone, but don't convince yourself you /cant/ due to your dysphoria making it so you want to pick yourself apart piece by piece.
You have your brothers and sisters standing beside you. And maybe talking to a gender counselor will help you get an impartial view on these issues, and someone to bounce thoughts off of who you can trust not to sugarcoat it.