That would have been a terrible thing to do. Again, wellying the throttle would just demand even more grip from the front tyres - and would ensure that the understeer skid continues.
The right things to do to control an understeer are as follows:
* If you're braking, ease off on the brakes. Use cadence braking only if your car doesn't have ABS. Otherwise, let the ABS do its job.
* If you're accelerating, gently ease off on the throttle. "Gently" being a key word here!
* Straighten the steering wheel slightly. This takes a lot of will-power because it feels like the wrong thing to do, but you've already exceeded the steering capability of the front tyres so you need to reduce the steering demand in order to allow the tyres to catch grip. It's a really odd feeling: you straighten the wheel and then the car actually starts to turn in and go where you wanted it to go - it really does work!
* In an extreme understeer where you're aquaplaning badly, you can rapidly "saw" the steering wheel back and forth to
help the tyres cut through the water. I was taught this method, but to be honest I doubt I'd have the presence of mind to actually do it in the heat of the moment.
All this stuff will be taught on a skid control training day. I really recommend it - it's fun and I learnt a lot.
Oh, and the other thing I missed off the list:
* Choose better tyres next time! From the picture, it looks like you're nearly ready for new tyres anyway...