Here's a little function to unfold the current element-at-point, given that it is a `src-block`:

```lang-el
#+begin_src elisp
  (defun my/org-show-block ()
    (let* ((e (org-element-at-point))
           (type (org-element-type e))
           (beg (org-element-property :begin e))
           (end (org-element-property :end e)))
      (when (eq type 'src-block)
          (org-fold-region beg end nil 'block))))
#+end_src
```
It's a no-op if the block is already unfolded.