Do you think I can get restitution for my agony?

What was the substance? Who put it there? How long was it there? If you can't answer those questions, you do not have a proveable case.

Can you prove who made the step wet? If so, you may have a claim.

Why is it that if you fall on my property you think I owe you something. I do not, you have to prove that the reason you fell was the fault of someone else. They were negligent not that there was water (which you cant prove) but there was something offensive there, they knew it or had a reasonable chance to know it, and failed to do anything (see how hard this is?) Then you have to prove damages. You also have to prove you were very careful and did nothing careless yourself.

Without knowing what you slipped on, I think you have an uphill battle. You have to know what it was and who put it there or allowed it to be there when they knew or should have known it was there. You don't seem to have that info.

It need to prove the business negligent. If they were unaware of the wet spot, they are not negligent. Also, you matter is to small for an attorney to take. You can request they pay your medical costs and, if they refuse you can take them to small claims.

In order to make a claim against a property owner (including stores, parking lots, apartments, etc) the injured party has to show that the owner either created the hazardous condition or else knew or should have known of the hazard, had an opportunity to correct it, and failed to take action. So, you would have to prove what it was that you slipped on and come up with evidence either that the store employees put it there (such as mopping the floor with excessive water) or that it was there for a long enough time that they should have noticed it and cleaned it up. There is another possibility: some business owners have what is called a medical payments provision of a liability insurance policy. Although it is not required, this provision will pay medical expenses up to a certain amount, regardless of fault.

You can get restitution for the medical bills if you prove negligence, although it is likely the insurer will be more than happy to pay to get rid of the case. If your bills are less than $5,000, you will probably be lucky to get $500-1000 for pain and suffering.

Merely because the stairs were wet does not make the landowner responsible; you have to prove they were negligent, by either allowing a situation to exist which made the steps wet (i.e., a leaking ceiling) or they knew the steps were wet and didn't timely take corrective steps to either warn patrons of the water or clean the liquid up. If someone who was walking down (or up) the stairs just a few minutes ahead of you spilled their drink, that landowner wouldn't be responsible under that factual scenario, but the burden is on you to prove how the water had gotten there or how long it had been there.