Note: Just realized the little brother was already named Tim, sorry for any confusion or ruining the immersion. I'm pressing forward with Daniel to keep from bouncing back and forth.
It was all of three minutes before there was a knock on the door. Your heart lept as anxiety washed over you, you hadn't felt the socks kick in yet but every other time they started working right away... heck, the change you're trying to undo was instantaneous and accidental... "I'm not decent; don't come in. Who is it?" you lied relaxing on your bed...
"It's me," Daniel called through the door...
You asked him for a favor and like the impatient 12-year-old he is, he wants to collect. Your immediate thought was to tell him to go away, he could stand to learn a little patience, "Now's not a good time kiddo." is what slipped out of your mouth... you winced, that was dad coming through again and it just skyrocketed how suspicious you were.
"What?! You're being weird and you owe me an explanation!" Dan insisted.
"UGH..." more complications! You realized you'd rather have him helping to keep the secret than trying to out you, or even just his tendency to mouth whatever goes through his brain which almost got you when he walked in.
Dan must have heard you groan because he was waiting quietly... You got up and went to the door bending down to where his head would be and softly said... "This has to be a secret. This has to STAY a secret." You cracked the door just enough so you can look each other in the eyes. "You can't tell mom, you can't tell dad, you can't tell your friends. This is me and you."
"Okay, sure..." he said nonchalantly expecting the door to open.
Irritated you continued. "This may scare you or you might think it's exciting or whatever else you may feel or think, but no matter what it stays between us."
He narrowed his eyes understanding that you are taking this more seriously than the run of the mill brotherly oath. "Alright. Us, nobody else... I promise."
"Cover your mouth when you come in and try not to be loud." You step back from the door, and open it wide enough for him to come in. You hear your parents continuing their fight from earlier in the kitchen, though quieter.
Daniel stepped in and looked at your room before settling on you. he didn't scream but easily made out that you looked different was struggling to formulate his question...
"There is a lot to this, sit down." you gestured to the bed... "So the other day I stopped at a shop..." 10 minutes later "... and then you knocked on my door."
"Dad was playing video games?" Dan asked in disbelief.
"That's the part you have trouble believing?" you laughed. "So I'm just waiting for these socks to make my hair go back to normal."
Dan squinted, "Woah, I think it did while you were talking, I didn't even notice! Wow."
Relieved you bolted to the bathroom examining your hair for yourself... It was no longer speckled with gray and though your facial hair was growing, it wasn't as dense, didn't reach as high on your cheeks, and didn't make a permanent shadow. In short, you no longer looked like a middle-aged man with a youthful face. You sighed in relief and looked at Danny, "Back to normal!"
"That's not normal. You're still taller and bigger, and you're growing a beard there..." Dan announced. getting an immediate glare from you.
"It's the new normal I told you about, and I can't undo it." you whispered harshly, "Yeah, it's called puberty!" you said in a normal voice... just in case mom or dad overheard. You motioned back to your room so you could talk more, and better he says stuff behind your shut door than in the hallway.
"So mom and dad really don't see it?" Dan asked.
"Of course they see it, but they don't know about the socks. So they could either decide to believe magic is real and assume something magically transformed their son, or they could assume their pubescent son had a growth spurt and they didn't notice till now. Which do you think is more likely?"
"I guess, but you're so different," Dan said.
"I know," you said a little sadly.
"And the socks only listed shoes as ways to activate them?"
"Yeah, but as I found out... sticking fingers in a shoe while someone else is transforming could do it... and mixing socks up... and I think we could expand shoes to footwear... I doubt it HAS to be intended for outdoor use... a slipper could probably work."
"What if you wore one shoe? What if you wore two different shoes? What if you wore two different shoes AND someone else's socks!" Dan asked.
"Dan! You're a genius!" you said slipping off the shoes.
"Bout time you recognized!" Dan said with a smirk.
You went to your sock drawer and found a pair of socks making sure they were definitely yours, maybe you could get back to your old self after all... and if socks can trigger the transformation, you have lots of options to get back to your normal body. You slip them on your feet and wait... "Footwear!" you said hopefully.