#1 Most likely you over sped the flaps causing damage which is preventing them from moving/closing all the way. Another possibility is the Landing Gear Fairing Door Emergency Release Handle has been pulled causing no hydraulic pressure.
#2 In normal operations, high blower mode starts automatically from 14,500 to 19,500 feet, depending on the amount of ram air being delivered through the carburetor. The supercharger can be controlled manually by a switch on the instrument panel (Left of the fuel booster switch) The switch has three positions – AUTOMATIC, LOW, and HIGH.