What to do f I’m a handy man I got a job that required another person, so I got a guy to help me out but he cut into himself with a saw?

It is impossible to answer your question without more information.  I have no idea what you mean by "I had to get materials when he hurt himself." 

Determining whether this is your fault or if you will get blamed for it has practical and theoretical aspects.  Did you do something to cause him to get hurt?  If you did, then theoretically it could be your fault or you could get blamed for it.  I don't practice law in Texas, but I would be surprised if you were automatically responsible for a helper getting hurt. 

As a practical matter, do you have insurance that would cover this man getting hurt?  I doubt it.  Are you a rich man from whom this helper can take a bunch of assets?  If so, I suggest you hire a lawyer right away to settle this thing.  If you are a hard-working guy with few assets and no insurance, I doubt that any lawyer would be interested in representing your helper in a claim against you.  If the two of you were working at a home, the owner's homeowner's insurance may pay the man's medical expenses.

My advice in situations like this usually is - do the right thing and keep your mouth shut.  Be caring and compassionate for the man who got hurt.  If you can help him pay his medical bills, do so.  Do not admit any fault, even if you think you have some.  Do not talk loosely with anyone about this.  If someone in authority (like a homeowner's insurance representative) asks you for a statement, answer the questions truthfully -- answer exactly what they asked you and nothing more.  Do not volunteer anything they did not ask. 

In these kind of situations, most people get all upset and think up a scheme to protect themselves from something that does not exist.  Don't do it.  What happened happened.   You cannot change it now.  Slow down.  Take some deep breaths.  Deal with what is actually happening right in front of you right now.  Do not allow yourself to think endlessly about what might happen. 

I hope this helps.  Good luck.