I know what you're thinking... "NUKE DoTs"?! But Flame! That's an oxymoron!" In my opinion, that is not true... with this build, your enemy will watch their health creep away, huge chunks at a time. However, at this stage, this build is not 100% legit (More like 80-90%), and you'd probably be better off in a 3v3 match, as this build requires you to focus one at a time more.

I like to take flat AP quints and glyphs, as they can give you about 24 AP at the start of the game. This is huge. This assures nice harass in lane, (more on that later) and easy farming, as your DoT can help you land last hits on minions.

Anyways, I like to get Greater Mark of Magic Penetration as 9 magic pierce can really help early game, and stacks nicely with the Archaic Knowledge mastery, and Sorcerer's Shoes.

I also get Greater Glyph of Ability Power and Greater Quintessence of Ability Power for, as I said, the flat AP.

Finally, I'd get Greater Seal of Scaling Magic Resist, for mid/late game, because Teemo lacks a lot of magic resist. But don't think since you have these runes, you can run in the middle the enemy do start attacking. No. Teemo is supposed to sit back, and bombard the enemy with poison, while happily letting the tank take all the damage.

Here's the thing. If you don't know why you should get these masteries, then you probably aren't even a high enough level to be able to get half of them. If you want to get different masteries, then please leave. These masteries relate directly to this type of champion build (AP carry).
So no, you cannot change it. Unless you really want to go a bit tanky, in exachange for some perfectly good utility, be my guest.

I start with Boots so I can kite around a bit in lane. This way I can dodge skill shots, run away when the enemy gets aggressive, or simply run faster during a chase. I then upgrade to Sorcerer's Shoes. Next, is two Dagger, to build into a Malady, which'll do nice magic damage every time you attack, while increasing your attack speed and AP. Next is a Sheen which gives you a nice 150% attack increase for you next attack when you use a skill, plus a bit of AP. This works great with your blind. Right after, is a Guinsoo's Rageblade which gives you AD and AP, and increases your Attack Speed and AP every attack. Next up is a Hextech Revolver for nice AP and spell vamp, to heal. Then, a Lich Bane will give you massive nuking power with your Blind; as it does great initial damage, and then your normal attack right after is increased by your current AP. Finally, I get Rabadon's Deathcap and Hextech Gunblade for lifesteal, and massive AP.