Not Updated For Current Season
The masteries shown here are not yet updated for the current season, the guide author needs to set up the new masteries. As such, they will be different than the masteries you see in-game.
This is my new Guide to the reworked Teemo in 184.108.40.206
I know it is an insanely expensive build, i havent managed to get all the items on the list EVER. As you dont get any items for hp or resists, you need a good team...
Max out toxic shot as this is the main dmg source.
Plant some shrooms in the brushes, so you have an alarm system for ganks on your lane,
use the rest of the brushes for farming - plant the shrooms in the middle of the lane, so the creeps hit them. This is also always your backup plan, if you need to go back to your base, and often turns going back into a kill :>
You MAY exchange the lichbane for a Rylais, so you have a slow and way more hp ...
To engage use exhaust on an enemy, so he cant hit you and cant run away, as soon as exhaust runs out, use blinding dart. If dont do enough dmg to kill them in that time, use blinding dart first, then exhaust and blind again. Thanks to Nashors Tooth, it should be ready again soon.
 Amplfying Tome + Heal Potion.
Stay defensive and focus on farming.
Use your Blinding dart to harass.
 Now try to get Malady and Nashor's Tooth as fast as possible
 You'll have to play pretty defensive because youre very squishy, therefore go into ganks with caution. Meaning always stay at a decent range and focus on the enemys squishies.