Did you delete or hide the line? If "Delete" then undo will help (If you haven't done anything else, and if you haven't restarted the IDE or changed project....
First of all, by default the IDE shows only every 5th line number, and dots on the lines in-between. However if you move the text-cursor (caret) through those line (e.g. with cursor down) then each line number will be shown.
So, if you place the cursor on line 1030, and then press cursor down, the editor should show the 1031 for the line you moved down to.
If you then press down ONCE again, does it show 1033 for the next line? Effectively leaving out 1032?
If the line is hidden, then some sort of symbol should be present on the left hand side. (And also a yellow box with dots at the end of one of the text lines / could be a different color).
See Image.
Below line 40 is one line HIDDEN and there is a small box with a down arrow. This will show it.
At line 46 are also some hidden lines. In this case it is a + in a box. (There is a reason for the 2 symbols, but ...)
You can also right click (context menu) on that vertical line between the boxes (anywhere on that line), and the context menu should show "unfold all".
If you do not have that line either there are key combos
ALT SHIFT 0
may unfold everything. BUT many operating systems hook that and it may not work. (WARNING, it may have your OS do things you don't want / change keyboard layout)
You can configure the key settings in "keymap" of the menu: Tools > Options
Search for "fold"
And you can make that line visible under "Editor > Display" in the same dialog (same menu entry). Look for fold/folding