Chevy Geo Car Questions

Hi there. I have a question about the Geo Metro 1992 LSI 3 cylinder. Why would my oil dipstick not fit back into the reservoir? Last nite I was checking the fluids in the car and then when it came to oil checking, I had one heck of a time just in removing the stick.Then after I cleaned it, I couldn't (and still can't) replace it completely . It can only be replaced 1/2 way. Dip stick is not broken/no signs of rust.