The expulsion of Palestinians is a politically charged phrase, because the number who were expelled varies between authors. A safe estimate is somewhere a bit below or above half, during the war.

As far as attitudes, it's hard to measure if they got better or worse. How do you measure "worse"? And is it related to the Nakba? It's hard to prove.

Pre-1948, there was definitely anti-Semitism. There were riots attacking Jews in 1920, 1921, and 1929, the last revolving mostly around a rumor that "the Jews" were planning to take over the Western Wall; a persistent theme that has been used to foment violence since, mostly related to the Temple Mount/Al Aqsa. Some of the violence was revolving around the growth of the Zionist movement and perceived displacement. The argument that Zionism would displace people without a doubt is uncertain. What is clear is that Palestinian Arabs did not like the idea, and that played into the violence.

Anti-Semitism had been trending upward throughout the Ottoman Empire in the 19th century regardless as well, even before the advent of Zionism. Anti-Semitic pogroms were on the rise, and occurred in Jerusalem in the 1840s, 1870s, and 1890s. The use of the blood libel (the claim that Jews kill Christian children) inspired violence in Damascus in the mid-19th century. The attempt to modernize inspired backlash, as Ottoman officials observed that the attempt to make all citizens equal and end the dhimmi system led some to say that they were unhappy being equal with Jews. Cevdet Pasha, and Ottoman official, had a pertinent quote:

whereas in former times, in the Ottoman State, the communities were ranked, with the Muslims first, then the Greeks, then the Armenians, then the Jews, now all of them were put on the same level. Some Greeks objected to this, saying: 'The government has put us together with the Jews. We were content with the supremacy of Islam.'

And there is another example of a traveler writing:

I have seen a little fellow of six years old, with a troop of fat toddlers of only three and four, teaching [them] to throw stones at a Jew, and one little urchin would, with the greatest coolness, waddle up to the man and literally spit upon his Jewish gaberdine. To all this the Jew is obliged to submit; it would be more than his life was worth to offer to strike a Mahommedan.

That's just one example. There are others. A Zionist immigrant, before Zionism seemed like a serious threat to most, wrote in 1885 that they suffered "attacks from Arabs" constantly, though it's hard to say if it was anti-Semitism.

Was it made worse? Well, it can't have been made better. But there was already a trend, so we can't separate out how much the increase might've gone had things gone differently.