raisins have 29 grams Sugar...okay to put in oatmeal?!

Hi!

Sure! Raisins add a nice flavour and a nice chewy texture to oatmeal. I always add them to mine. You don't need very many so it is fine! Enjoy!

That would be 29 grams of natural sugar not 29 grams of processed sugar.
Our body handle the sugar we get in fruits in a much less aggressive manner then it does process sugar; processed sugars enter into our system in such a compact manner, that the body tends to release more insulin then necessary.
Raisins were grapes, grapes are fruits, thus body friendly; I have eaten oatmeal with raisins and found not problems associated with doing such.
Moderation is the key, 24 raisins would led to diabetes.
If you are young, you'll surely burn off that sugar energy in no time.
Eat & enjoy.

That much sugar won't turn you into a diabetic!

The recommended daily allowance of sugar is about 90g, so this is well within your limits so long as you watch out on other foods and drinks you're having that contain sugar.

You could also consider not putting a whole box in at a time.

No. Never okay! Just one raisin contains enough sugar to kill a man.