As he said ^
Maybe there was some trapped naphtha in the crystals which redissolved them as it got warm.. If you scrape and re-scrape it a bit, it might harden up, though possibly it will be more waxy than crystals, but it should be fine to consume.
If for some reason even airdrying for long and scraping it and moving it around doesnt harden it up, then it probably formed some n-oxide which is more oily, but its also perfectly psychoactive.. In that case you can dissolve it in a small amount of non-denatured ethanol or acetone or similar, add to a small amount of herbs, and let it dry. If you weigh your herbs before and after, you will know how much dmt there is. Calculate as if you have around 1% dmt from your mimosa (if you did 4x pulls and they are all together in that container), and add the equivalent amount of herbs so that its around 1:1 ratio dmt:herbs