Is self creation possible? I don't know what you're talking about.
You can come up with any number of cases in which there does 'not' seem to be causation. What's the point in that?
The ball and cushion case is a case in which the depression is being caused by the ball and we do not need to know whether the ball was ever not on the cushion in order to be able to conclude that the ball is causing the depression.
And I gave TWO examples. As you are clearly having trouble with the first one, question beggingly insisting that we have to know if the ball was ever not on the cushion before we can conclude that it is causing the depression, why not focus on the other example? Only one has to work.
Presumably you accept that not every event can be caused by a prior event, for then one would have to posit an actual infinity of prior events. So, all events must ultimately trace to causes that are not events, but things.
So, substances can cause events. But when do substances cause the events that they cause? Well, when the events occur. That is simultaneous causation. So, unless simultaneous causation makes sense, it seems event causation won't make sense either.
And if simultaneous causation makes sense, then there seems to be nothing incoherent about self-creation.