my_lm <- lm(Dim4 ~ Category*Region, data=df)
summary(my_lm)
Anova(my_lm, type = "III")

TukeyHSD(aov(my_lm), ordered=TRUE)

$Category
                            diff          lwr      upr     p adj
Tweets-Conversations   0.6843803 -0.279052730 1.647813 0.2961601
Comments-Conversations 1.6552203  0.665253423 2.645187 0.0000540
$Region
          diff       lwr      upr p adj
US-PK 1.146865 0.7036846 1.590046 5e-07

$`Category:Region`
                                        diff         lwr      upr     p adj
Conversations:US-Tweets:PK        0.04138269 -1.46974284 1.552508 1.0000000
Conversations:PK-Tweets:PK        0.30818926 -1.31628692 1.932665 0.9998612
Comments:PK-Tweets:PK             1.20670619 -0.35032424 2.763737 0.2931398
Tweets:US-Tweets:PK               1.78097509  0.24027735 3.321673 0.0097448