I would call your local fish and wildlife and see if they can get someone out there to try and trap it or something. Or at least get some advice from professionals on how to proceed.
And pack a stoudt handgun, just in case (hey, you're in texas anyway, right?
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Mountain lion attacks are pretty rare- but they happen. Based on the stats i saw in the sites i linked to in the bear forum, it seems like most attacks are against kids, but they will attack adults too. Check out the link in the Bear thread too, it has a lot of what did/did not work for previous people confronted by cat attacks.